deba@326: /* -*- mode: C++; indent-tabs-mode: nil; -*-
deba@326: *
deba@326: * This file is a part of LEMON, a generic C++ optimization library.
deba@326: *
deba@326: * Copyright (C) 2003-2008
deba@326: * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@326: * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@326: *
deba@326: * Permission to use, modify and distribute this software is granted
deba@326: * provided that this copyright notice appears in all copies. For
deba@326: * precise terms see the accompanying LICENSE file.
deba@326: *
deba@326: * This software is provided "AS IS" with no warranty of any kind,
deba@326: * express or implied, and with no claim as to its suitability for any
deba@326: * purpose.
deba@326: *
deba@326: */
deba@326:
deba@326: #ifndef LEMON_MAX_MATCHING_H
deba@326: #define LEMON_MAX_MATCHING_H
deba@326:
deba@326: #include <vector>
deba@326: #include <queue>
deba@326: #include <set>
deba@326: #include <limits>
deba@326:
deba@326: #include <lemon/core.h>
deba@326: #include <lemon/unionfind.h>
deba@326: #include <lemon/bin_heap.h>
deba@326: #include <lemon/maps.h>
deba@326:
deba@326: ///\ingroup matching
deba@326: ///\file
deba@327: ///\brief Maximum matching algorithms in general graphs.
deba@326:
deba@326: namespace lemon {
deba@326:
deba@327: /// \ingroup matching
deba@326: ///
deba@327: /// \brief Edmonds' alternating forest maximum matching algorithm.
deba@326: ///
alpar@330: /// This class implements Edmonds' alternating forest matching
alpar@330: /// algorithm. The algorithm can be started from an arbitrary initial
alpar@330: /// matching (the default is the empty one)
deba@326: ///
alpar@330: /// The dual solution of the problem is a map of the nodes to
deba@327: /// MaxMatching::Status, having values \c EVEN/D, \c ODD/A and \c
deba@327: /// MATCHED/C showing the Gallai-Edmonds decomposition of the
deba@327: /// graph. The nodes in \c EVEN/D induce a graph with
deba@327: /// factor-critical components, the nodes in \c ODD/A form the
deba@327: /// barrier, and the nodes in \c MATCHED/C induce a graph having a
alpar@330: /// perfect matching. The number of the factor-critical components
deba@327: /// minus the number of barrier nodes is a lower bound on the
alpar@330: /// unmatched nodes, and the matching is optimal if and only if this bound is
deba@327: /// tight. This decomposition can be attained by calling \c
deba@327: /// decomposition() after running the algorithm.
deba@326: ///
deba@327: /// \param _Graph The graph type the algorithm runs on.
deba@327: template <typename _Graph>
deba@326: class MaxMatching {
deba@327: public:
deba@327:
deba@327: typedef _Graph Graph;
deba@327: typedef typename Graph::template NodeMap<typename Graph::Arc>
deba@327: MatchingMap;
deba@327:
deba@327: ///\brief Indicates the Gallai-Edmonds decomposition of the graph.
deba@327: ///
alpar@330: ///Indicates the Gallai-Edmonds decomposition of the graph. The
deba@327: ///nodes with Status \c EVEN/D induce a graph with factor-critical
deba@327: ///components, the nodes in \c ODD/A form the canonical barrier,
deba@327: ///and the nodes in \c MATCHED/C induce a graph having a perfect
deba@327: ///matching.
deba@327: enum Status {
deba@327: EVEN = 1, D = 1, MATCHED = 0, C = 0, ODD = -1, A = -1, UNMATCHED = -2
deba@327: };
deba@327:
deba@327: typedef typename Graph::template NodeMap<Status> StatusMap;
deba@327:
deba@327: private:
deba@326:
deba@326: TEMPLATE_GRAPH_TYPEDEFS(Graph);
deba@326:
deba@327: typedef UnionFindEnum<IntNodeMap> BlossomSet;
deba@327: typedef ExtendFindEnum<IntNodeMap> TreeSet;
deba@327: typedef RangeMap<Node> NodeIntMap;
deba@327: typedef MatchingMap EarMap;
deba@327: typedef std::vector<Node> NodeQueue;
deba@327:
deba@327: const Graph& _graph;
deba@327: MatchingMap* _matching;
deba@327: StatusMap* _status;
deba@327:
deba@327: EarMap* _ear;
deba@327:
deba@327: IntNodeMap* _blossom_set_index;
deba@327: BlossomSet* _blossom_set;
deba@327: NodeIntMap* _blossom_rep;
deba@327:
deba@327: IntNodeMap* _tree_set_index;
deba@327: TreeSet* _tree_set;
deba@327:
deba@327: NodeQueue _node_queue;
deba@327: int _process, _postpone, _last;
deba@327:
deba@327: int _node_num;
deba@327:
deba@327: private:
deba@327:
deba@327: void createStructures() {
deba@327: _node_num = countNodes(_graph);
deba@327: if (!_matching) {
deba@327: _matching = new MatchingMap(_graph);
deba@327: }
deba@327: if (!_status) {
deba@327: _status = new StatusMap(_graph);
deba@327: }
deba@327: if (!_ear) {
deba@327: _ear = new EarMap(_graph);
deba@327: }
deba@327: if (!_blossom_set) {
deba@327: _blossom_set_index = new IntNodeMap(_graph);
deba@327: _blossom_set = new BlossomSet(*_blossom_set_index);
deba@327: }
deba@327: if (!_blossom_rep) {
deba@327: _blossom_rep = new NodeIntMap(_node_num);
deba@327: }
deba@327: if (!_tree_set) {
deba@327: _tree_set_index = new IntNodeMap(_graph);
deba@327: _tree_set = new TreeSet(*_tree_set_index);
deba@327: }
deba@327: _node_queue.resize(_node_num);
deba@327: }
deba@327:
deba@327: void destroyStructures() {
deba@327: if (_matching) {
deba@327: delete _matching;
deba@327: }
deba@327: if (_status) {
deba@327: delete _status;
deba@327: }
deba@327: if (_ear) {
deba@327: delete _ear;
deba@327: }
deba@327: if (_blossom_set) {
deba@327: delete _blossom_set;
deba@327: delete _blossom_set_index;
deba@327: }
deba@327: if (_blossom_rep) {
deba@327: delete _blossom_rep;
deba@327: }
deba@327: if (_tree_set) {
deba@327: delete _tree_set_index;
deba@327: delete _tree_set;
deba@327: }
deba@327: }
deba@327:
deba@327: void processDense(const Node& n) {
deba@327: _process = _postpone = _last = 0;
deba@327: _node_queue[_last++] = n;
deba@327:
deba@327: while (_process != _last) {
deba@327: Node u = _node_queue[_process++];
deba@327: for (OutArcIt a(_graph, u); a != INVALID; ++a) {
deba@327: Node v = _graph.target(a);
deba@327: if ((*_status)[v] == MATCHED) {
deba@327: extendOnArc(a);
deba@327: } else if ((*_status)[v] == UNMATCHED) {
deba@327: augmentOnArc(a);
deba@327: return;
deba@327: }
deba@327: }
deba@327: }
deba@327:
deba@327: while (_postpone != _last) {
deba@327: Node u = _node_queue[_postpone++];
deba@327:
deba@327: for (OutArcIt a(_graph, u); a != INVALID ; ++a) {
deba@327: Node v = _graph.target(a);
deba@327:
deba@327: if ((*_status)[v] == EVEN) {
deba@327: if (_blossom_set->find(u) != _blossom_set->find(v)) {
deba@327: shrinkOnEdge(a);
deba@327: }
deba@327: }
deba@327:
deba@327: while (_process != _last) {
deba@327: Node w = _node_queue[_process++];
deba@327: for (OutArcIt b(_graph, w); b != INVALID; ++b) {
deba@327: Node x = _graph.target(b);
deba@327: if ((*_status)[x] == MATCHED) {
deba@327: extendOnArc(b);
deba@327: } else if ((*_status)[x] == UNMATCHED) {
deba@327: augmentOnArc(b);
deba@327: return;
deba@327: }
deba@327: }
deba@327: }
deba@327: }
deba@327: }
deba@327: }
deba@327:
deba@327: void processSparse(const Node& n) {
deba@327: _process = _last = 0;
deba@327: _node_queue[_last++] = n;
deba@327: while (_process != _last) {
deba@327: Node u = _node_queue[_process++];
deba@327: for (OutArcIt a(_graph, u); a != INVALID; ++a) {
deba@327: Node v = _graph.target(a);
deba@327:
deba@327: if ((*_status)[v] == EVEN) {
deba@327: if (_blossom_set->find(u) != _blossom_set->find(v)) {
deba@327: shrinkOnEdge(a);
deba@327: }
deba@327: } else if ((*_status)[v] == MATCHED) {
deba@327: extendOnArc(a);
deba@327: } else if ((*_status)[v] == UNMATCHED) {
deba@327: augmentOnArc(a);
deba@327: return;
deba@327: }
deba@327: }
deba@327: }
deba@327: }
deba@327:
deba@327: void shrinkOnEdge(const Edge& e) {
deba@327: Node nca = INVALID;
deba@327:
deba@327: {
deba@327: std::set<Node> left_set, right_set;
deba@327:
deba@327: Node left = (*_blossom_rep)[_blossom_set->find(_graph.u(e))];
deba@327: left_set.insert(left);
deba@327:
deba@327: Node right = (*_blossom_rep)[_blossom_set->find(_graph.v(e))];
deba@327: right_set.insert(right);
deba@327:
deba@327: while (true) {
deba@327: if ((*_matching)[left] == INVALID) break;
deba@327: left = _graph.target((*_matching)[left]);
deba@327: left = (*_blossom_rep)[_blossom_set->
deba@327: find(_graph.target((*_ear)[left]))];
deba@327: if (right_set.find(left) != right_set.end()) {
deba@327: nca = left;
deba@327: break;
deba@327: }
deba@327: left_set.insert(left);
deba@327:
deba@327: if ((*_matching)[right] == INVALID) break;
deba@327: right = _graph.target((*_matching)[right]);
deba@327: right = (*_blossom_rep)[_blossom_set->
deba@327: find(_graph.target((*_ear)[right]))];
deba@327: if (left_set.find(right) != left_set.end()) {
deba@327: nca = right;
deba@327: break;
deba@327: }
deba@327: right_set.insert(right);
deba@327: }
deba@327:
deba@327: if (nca == INVALID) {
deba@327: if ((*_matching)[left] == INVALID) {
deba@327: nca = right;
deba@327: while (left_set.find(nca) == left_set.end()) {
deba@327: nca = _graph.target((*_matching)[nca]);
deba@327: nca =(*_blossom_rep)[_blossom_set->
deba@327: find(_graph.target((*_ear)[nca]))];
deba@327: }
deba@327: } else {
deba@327: nca = left;
deba@327: while (right_set.find(nca) == right_set.end()) {
deba@327: nca = _graph.target((*_matching)[nca]);
deba@327: nca = (*_blossom_rep)[_blossom_set->
deba@327: find(_graph.target((*_ear)[nca]))];
deba@327: }
deba@327: }
deba@327: }
deba@327: }
deba@327:
deba@327: {
deba@327:
deba@327: Node node = _graph.u(e);
deba@327: Arc arc = _graph.direct(e, true);
deba@327: Node base = (*_blossom_rep)[_blossom_set->find(node)];
deba@327:
deba@327: while (base != nca) {
deba@327: _ear->set(node, arc);
deba@327:
deba@327: Node n = node;
deba@327: while (n != base) {
deba@327: n = _graph.target((*_matching)[n]);
deba@327: Arc a = (*_ear)[n];
deba@327: n = _graph.target(a);
deba@327: _ear->set(n, _graph.oppositeArc(a));
deba@327: }
deba@327: node = _graph.target((*_matching)[base]);
deba@327: _tree_set->erase(base);
deba@327: _tree_set->erase(node);
deba@327: _blossom_set->insert(node, _blossom_set->find(base));
deba@327: _status->set(node, EVEN);
deba@327: _node_queue[_last++] = node;
deba@327: arc = _graph.oppositeArc((*_ear)[node]);
deba@327: node = _graph.target((*_ear)[node]);
deba@327: base = (*_blossom_rep)[_blossom_set->find(node)];
deba@327: _blossom_set->join(_graph.target(arc), base);
deba@327: }
deba@327: }
deba@327:
deba@327: _blossom_rep->set(_blossom_set->find(nca), nca);
deba@327:
deba@327: {
deba@327:
deba@327: Node node = _graph.v(e);
deba@327: Arc arc = _graph.direct(e, false);
deba@327: Node base = (*_blossom_rep)[_blossom_set->find(node)];
deba@327:
deba@327: while (base != nca) {
deba@327: _ear->set(node, arc);
deba@327:
deba@327: Node n = node;
deba@327: while (n != base) {
deba@327: n = _graph.target((*_matching)[n]);
deba@327: Arc a = (*_ear)[n];
deba@327: n = _graph.target(a);
deba@327: _ear->set(n, _graph.oppositeArc(a));
deba@327: }
deba@327: node = _graph.target((*_matching)[base]);
deba@327: _tree_set->erase(base);
deba@327: _tree_set->erase(node);
deba@327: _blossom_set->insert(node, _blossom_set->find(base));
deba@327: _status->set(node, EVEN);
deba@327: _node_queue[_last++] = node;
deba@327: arc = _graph.oppositeArc((*_ear)[node]);
deba@327: node = _graph.target((*_ear)[node]);
deba@327: base = (*_blossom_rep)[_blossom_set->find(node)];
deba@327: _blossom_set->join(_graph.target(arc), base);
deba@327: }
deba@327: }
deba@327:
deba@327: _blossom_rep->set(_blossom_set->find(nca), nca);
deba@327: }
deba@327:
deba@327:
deba@327:
deba@327: void extendOnArc(const Arc& a) {
deba@327: Node base = _graph.source(a);
deba@327: Node odd = _graph.target(a);
deba@327:
deba@327: _ear->set(odd, _graph.oppositeArc(a));
deba@327: Node even = _graph.target((*_matching)[odd]);
deba@327: _blossom_rep->set(_blossom_set->insert(even), even);
deba@327: _status->set(odd, ODD);
deba@327: _status->set(even, EVEN);
deba@327: int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(base)]);
deba@327: _tree_set->insert(odd, tree);
deba@327: _tree_set->insert(even, tree);
deba@327: _node_queue[_last++] = even;
deba@327:
deba@327: }
deba@327:
deba@327: void augmentOnArc(const Arc& a) {
deba@327: Node even = _graph.source(a);
deba@327: Node odd = _graph.target(a);
deba@327:
deba@327: int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(even)]);
deba@327:
deba@327: _matching->set(odd, _graph.oppositeArc(a));
deba@327: _status->set(odd, MATCHED);
deba@327:
deba@327: Arc arc = (*_matching)[even];
deba@327: _matching->set(even, a);
deba@327:
deba@327: while (arc != INVALID) {
deba@327: odd = _graph.target(arc);
deba@327: arc = (*_ear)[odd];
deba@327: even = _graph.target(arc);
deba@327: _matching->set(odd, arc);
deba@327: arc = (*_matching)[even];
deba@327: _matching->set(even, _graph.oppositeArc((*_matching)[odd]));
deba@327: }
deba@327:
deba@327: for (typename TreeSet::ItemIt it(*_tree_set, tree);
deba@327: it != INVALID; ++it) {
deba@327: if ((*_status)[it] == ODD) {
deba@327: _status->set(it, MATCHED);
deba@327: } else {
deba@327: int blossom = _blossom_set->find(it);
deba@327: for (typename BlossomSet::ItemIt jt(*_blossom_set, blossom);
deba@327: jt != INVALID; ++jt) {
deba@327: _status->set(jt, MATCHED);
deba@327: }
deba@327: _blossom_set->eraseClass(blossom);
deba@327: }
deba@327: }
deba@327: _tree_set->eraseClass(tree);
deba@327:
deba@327: }
deba@326:
deba@326: public:
deba@326:
deba@327: /// \brief Constructor
deba@326: ///
deba@327: /// Constructor.
deba@327: MaxMatching(const Graph& graph)
deba@327: : _graph(graph), _matching(0), _status(0), _ear(0),
deba@327: _blossom_set_index(0), _blossom_set(0), _blossom_rep(0),
deba@327: _tree_set_index(0), _tree_set(0) {}
deba@327:
deba@327: ~MaxMatching() {
deba@327: destroyStructures();
deba@327: }
deba@327:
deba@327: /// \name Execution control
alpar@330: /// The simplest way to execute the algorithm is to use the
deba@327: /// \c run() member function.
deba@327: /// \n
deba@327:
alpar@330: /// If you need better control on the execution, you must call
deba@327: /// \ref init(), \ref greedyInit() or \ref matchingInit()
alpar@330: /// functions first, then you can start the algorithm with the \ref
deba@327: /// startParse() or startDense() functions.
deba@327:
deba@327: ///@{
deba@327:
deba@327: /// \brief Sets the actual matching to the empty matching.
deba@326: ///
deba@327: /// Sets the actual matching to the empty matching.
deba@326: ///
deba@326: void init() {
deba@327: createStructures();
deba@327: for(NodeIt n(_graph); n != INVALID; ++n) {
deba@327: _matching->set(n, INVALID);
deba@327: _status->set(n, UNMATCHED);
deba@326: }
deba@326: }
deba@326:
alpar@330: ///\brief Finds an initial matching in a greedy way
deba@326: ///
alpar@330: ///It finds an initial matching in a greedy way.
deba@326: void greedyInit() {
deba@327: createStructures();
deba@327: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@327: _matching->set(n, INVALID);
deba@327: _status->set(n, UNMATCHED);
deba@326: }
deba@327: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@327: if ((*_matching)[n] == INVALID) {
deba@327: for (OutArcIt a(_graph, n); a != INVALID ; ++a) {
deba@327: Node v = _graph.target(a);
deba@327: if ((*_matching)[v] == INVALID && v != n) {
deba@327: _matching->set(n, a);
deba@327: _status->set(n, MATCHED);
deba@327: _matching->set(v, _graph.oppositeArc(a));
deba@327: _status->set(v, MATCHED);
deba@326: break;
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@327:
alpar@330: /// \brief Initialize the matching from a map containing.
deba@326: ///
deba@327: /// Initialize the matching from a \c bool valued \c Edge map. This
deba@327: /// map must have the property that there are no two incident edges
deba@327: /// with true value, ie. it contains a matching.
deba@327: /// \return %True if the map contains a matching.
deba@327: template <typename MatchingMap>
deba@327: bool matchingInit(const MatchingMap& matching) {
deba@327: createStructures();
deba@327:
deba@327: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@327: _matching->set(n, INVALID);
deba@327: _status->set(n, UNMATCHED);
deba@326: }
deba@327: for(EdgeIt e(_graph); e!=INVALID; ++e) {
deba@327: if (matching[e]) {
deba@327:
deba@327: Node u = _graph.u(e);
deba@327: if ((*_matching)[u] != INVALID) return false;
deba@327: _matching->set(u, _graph.direct(e, true));
deba@327: _status->set(u, MATCHED);
deba@327:
deba@327: Node v = _graph.v(e);
deba@327: if ((*_matching)[v] != INVALID) return false;
deba@327: _matching->set(v, _graph.direct(e, false));
deba@327: _status->set(v, MATCHED);
deba@327: }
deba@327: }
deba@327: return true;
deba@326: }
deba@326:
deba@327: /// \brief Starts Edmonds' algorithm
deba@326: ///
deba@327: /// If runs the original Edmonds' algorithm.
deba@327: void startSparse() {
deba@327: for(NodeIt n(_graph); n != INVALID; ++n) {
deba@327: if ((*_status)[n] == UNMATCHED) {
deba@327: (*_blossom_rep)[_blossom_set->insert(n)] = n;
deba@327: _tree_set->insert(n);
deba@327: _status->set(n, EVEN);
deba@327: processSparse(n);
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@327: /// \brief Starts Edmonds' algorithm.
deba@326: ///
deba@327: /// It runs Edmonds' algorithm with a heuristic of postponing
alpar@330: /// shrinks, therefore resulting in a faster algorithm for dense graphs.
deba@327: void startDense() {
deba@327: for(NodeIt n(_graph); n != INVALID; ++n) {
deba@327: if ((*_status)[n] == UNMATCHED) {
deba@327: (*_blossom_rep)[_blossom_set->insert(n)] = n;
deba@327: _tree_set->insert(n);
deba@327: _status->set(n, EVEN);
deba@327: processDense(n);
deba@327: }
deba@327: }
deba@327: }
deba@327:
deba@327:
deba@327: /// \brief Runs Edmonds' algorithm
deba@327: ///
deba@327: /// Runs Edmonds' algorithm for sparse graphs (<tt>m<2*n</tt>)
deba@327: /// or Edmonds' algorithm with a heuristic of
deba@327: /// postponing shrinks for dense graphs.
deba@326: void run() {
deba@327: if (countEdges(_graph) < 2 * countNodes(_graph)) {
deba@326: greedyInit();
deba@326: startSparse();
deba@326: } else {
deba@326: init();
deba@326: startDense();
deba@326: }
deba@326: }
deba@326:
deba@327: /// @}
deba@327:
deba@327: /// \name Primal solution
alpar@330: /// Functions to get the primal solution, ie. the matching.
deba@327:
deba@327: /// @{
deba@326:
alpar@330: ///\brief Returns the size of the current matching.
deba@326: ///
alpar@330: ///Returns the size of the current matching. After \ref
deba@327: ///run() it returns the size of the maximum matching in the graph.
deba@327: int matchingSize() const {
deba@327: int size = 0;
deba@327: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@327: if ((*_matching)[n] != INVALID) {
deba@327: ++size;
deba@326: }
deba@326: }
deba@327: return size / 2;
deba@326: }
deba@326:
deba@327: /// \brief Returns true when the edge is in the matching.
deba@327: ///
deba@327: /// Returns true when the edge is in the matching.
deba@327: bool matching(const Edge& edge) const {
deba@327: return edge == (*_matching)[_graph.u(edge)];
deba@327: }
deba@327:
deba@327: /// \brief Returns the matching edge incident to the given node.
deba@327: ///
deba@327: /// Returns the matching edge of a \c node in the actual matching or
deba@327: /// INVALID if the \c node is not covered by the actual matching.
deba@327: Arc matching(const Node& n) const {
deba@327: return (*_matching)[n];
deba@327: }
deba@326:
deba@326: ///\brief Returns the mate of a node in the actual matching.
deba@326: ///
deba@327: ///Returns the mate of a \c node in the actual matching or
deba@327: ///INVALID if the \c node is not covered by the actual matching.
deba@327: Node mate(const Node& n) const {
deba@327: return (*_matching)[n] != INVALID ?
deba@327: _graph.target((*_matching)[n]) : INVALID;
deba@326: }
deba@326:
deba@327: /// @}
deba@327:
deba@327: /// \name Dual solution
alpar@330: /// Functions to get the dual solution, ie. the decomposition.
deba@327:
deba@327: /// @{
deba@326:
deba@326: /// \brief Returns the class of the node in the Edmonds-Gallai
deba@326: /// decomposition.
deba@326: ///
deba@326: /// Returns the class of the node in the Edmonds-Gallai
deba@326: /// decomposition.
deba@327: Status decomposition(const Node& n) const {
deba@327: return (*_status)[n];
deba@326: }
deba@326:
deba@326: /// \brief Returns true when the node is in the barrier.
deba@326: ///
deba@326: /// Returns true when the node is in the barrier.
deba@327: bool barrier(const Node& n) const {
deba@327: return (*_status)[n] == ODD;
deba@326: }
deba@326:
deba@327: /// @}
deba@326:
deba@326: };
deba@326:
deba@326: /// \ingroup matching
deba@326: ///
deba@326: /// \brief Weighted matching in general graphs
deba@326: ///
deba@326: /// This class provides an efficient implementation of Edmond's
deba@326: /// maximum weighted matching algorithm. The implementation is based
deba@326: /// on extensive use of priority queues and provides
deba@326: /// \f$O(nm\log(n))\f$ time complexity.
deba@326: ///
deba@326: /// The maximum weighted matching problem is to find undirected
deba@327: /// edges in the graph with maximum overall weight and no two of
deba@327: /// them shares their ends. The problem can be formulated with the
deba@327: /// following linear program.
deba@326: /// \f[ \sum_{e \in \delta(u)}x_e \le 1 \quad \forall u\in V\f]
deba@327: /** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2}
deba@327: \quad \forall B\in\mathcal{O}\f] */
deba@326: /// \f[x_e \ge 0\quad \forall e\in E\f]
deba@326: /// \f[\max \sum_{e\in E}x_ew_e\f]
deba@327: /// where \f$\delta(X)\f$ is the set of edges incident to a node in
deba@327: /// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in
deba@327: /// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality
deba@327: /// subsets of the nodes.
deba@326: ///
deba@326: /// The algorithm calculates an optimal matching and a proof of the
deba@326: /// optimality. The solution of the dual problem can be used to check
deba@327: /// the result of the algorithm. The dual linear problem is the
deba@327: /** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}
deba@327: z_B \ge w_{uv} \quad \forall uv\in E\f] */
deba@326: /// \f[y_u \ge 0 \quad \forall u \in V\f]
deba@326: /// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f]
deba@327: /** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}}
deba@327: \frac{\vert B \vert - 1}{2}z_B\f] */
deba@326: ///
deba@326: /// The algorithm can be executed with \c run() or the \c init() and
deba@326: /// then the \c start() member functions. After it the matching can
deba@326: /// be asked with \c matching() or mate() functions. The dual
deba@326: /// solution can be get with \c nodeValue(), \c blossomNum() and \c
deba@326: /// blossomValue() members and \ref MaxWeightedMatching::BlossomIt
alpar@330: /// "BlossomIt" nested class, which is able to iterate on the nodes
deba@326: /// of a blossom. If the value type is integral then the dual
deba@326: /// solution is multiplied by \ref MaxWeightedMatching::dualScale "4".
deba@326: template <typename _Graph,
deba@326: typename _WeightMap = typename _Graph::template EdgeMap<int> >
deba@326: class MaxWeightedMatching {
deba@326: public:
deba@326:
deba@326: typedef _Graph Graph;
deba@326: typedef _WeightMap WeightMap;
deba@326: typedef typename WeightMap::Value Value;
deba@326:
deba@326: /// \brief Scaling factor for dual solution
deba@326: ///
deba@326: /// Scaling factor for dual solution, it is equal to 4 or 1
deba@326: /// according to the value type.
deba@326: static const int dualScale =
deba@326: std::numeric_limits<Value>::is_integer ? 4 : 1;
deba@326:
deba@326: typedef typename Graph::template NodeMap<typename Graph::Arc>
deba@326: MatchingMap;
deba@326:
deba@326: private:
deba@326:
deba@326: TEMPLATE_GRAPH_TYPEDEFS(Graph);
deba@326:
deba@326: typedef typename Graph::template NodeMap<Value> NodePotential;
deba@326: typedef std::vector<Node> BlossomNodeList;
deba@326:
deba@326: struct BlossomVariable {
deba@326: int begin, end;
deba@326: Value value;
deba@326:
deba@326: BlossomVariable(int _begin, int _end, Value _value)
deba@326: : begin(_begin), end(_end), value(_value) {}
deba@326:
deba@326: };
deba@326:
deba@326: typedef std::vector<BlossomVariable> BlossomPotential;
deba@326:
deba@326: const Graph& _graph;
deba@326: const WeightMap& _weight;
deba@326:
deba@326: MatchingMap* _matching;
deba@326:
deba@326: NodePotential* _node_potential;
deba@326:
deba@326: BlossomPotential _blossom_potential;
deba@326: BlossomNodeList _blossom_node_list;
deba@326:
deba@326: int _node_num;
deba@326: int _blossom_num;
deba@326:
deba@326: typedef RangeMap<int> IntIntMap;
deba@326:
deba@326: enum Status {
deba@326: EVEN = -1, MATCHED = 0, ODD = 1, UNMATCHED = -2
deba@326: };
deba@326:
deba@327: typedef HeapUnionFind<Value, IntNodeMap> BlossomSet;
deba@326: struct BlossomData {
deba@326: int tree;
deba@326: Status status;
deba@326: Arc pred, next;
deba@326: Value pot, offset;
deba@326: Node base;
deba@326: };
deba@326:
deba@327: IntNodeMap *_blossom_index;
deba@326: BlossomSet *_blossom_set;
deba@326: RangeMap<BlossomData>* _blossom_data;
deba@326:
deba@327: IntNodeMap *_node_index;
deba@327: IntArcMap *_node_heap_index;
deba@326:
deba@326: struct NodeData {
deba@326:
deba@327: NodeData(IntArcMap& node_heap_index)
deba@326: : heap(node_heap_index) {}
deba@326:
deba@326: int blossom;
deba@326: Value pot;
deba@327: BinHeap<Value, IntArcMap> heap;
deba@326: std::map<int, Arc> heap_index;
deba@326:
deba@326: int tree;
deba@326: };
deba@326:
deba@326: RangeMap<NodeData>* _node_data;
deba@326:
deba@326: typedef ExtendFindEnum<IntIntMap> TreeSet;
deba@326:
deba@326: IntIntMap *_tree_set_index;
deba@326: TreeSet *_tree_set;
deba@326:
deba@327: IntNodeMap *_delta1_index;
deba@327: BinHeap<Value, IntNodeMap> *_delta1;
deba@326:
deba@326: IntIntMap *_delta2_index;
deba@326: BinHeap<Value, IntIntMap> *_delta2;
deba@326:
deba@327: IntEdgeMap *_delta3_index;
deba@327: BinHeap<Value, IntEdgeMap> *_delta3;
deba@326:
deba@326: IntIntMap *_delta4_index;
deba@326: BinHeap<Value, IntIntMap> *_delta4;
deba@326:
deba@326: Value _delta_sum;
deba@326:
deba@326: void createStructures() {
deba@326: _node_num = countNodes(_graph);
deba@326: _blossom_num = _node_num * 3 / 2;
deba@326:
deba@326: if (!_matching) {
deba@326: _matching = new MatchingMap(_graph);
deba@326: }
deba@326: if (!_node_potential) {
deba@326: _node_potential = new NodePotential(_graph);
deba@326: }
deba@326: if (!_blossom_set) {
deba@327: _blossom_index = new IntNodeMap(_graph);
deba@326: _blossom_set = new BlossomSet(*_blossom_index);
deba@326: _blossom_data = new RangeMap<BlossomData>(_blossom_num);
deba@326: }
deba@326:
deba@326: if (!_node_index) {
deba@327: _node_index = new IntNodeMap(_graph);
deba@327: _node_heap_index = new IntArcMap(_graph);
deba@326: _node_data = new RangeMap<NodeData>(_node_num,
deba@326: NodeData(*_node_heap_index));
deba@326: }
deba@326:
deba@326: if (!_tree_set) {
deba@326: _tree_set_index = new IntIntMap(_blossom_num);
deba@326: _tree_set = new TreeSet(*_tree_set_index);
deba@326: }
deba@326: if (!_delta1) {
deba@327: _delta1_index = new IntNodeMap(_graph);
deba@327: _delta1 = new BinHeap<Value, IntNodeMap>(*_delta1_index);
deba@326: }
deba@326: if (!_delta2) {
deba@326: _delta2_index = new IntIntMap(_blossom_num);
deba@326: _delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index);
deba@326: }
deba@326: if (!_delta3) {
deba@327: _delta3_index = new IntEdgeMap(_graph);
deba@327: _delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index);
deba@326: }
deba@326: if (!_delta4) {
deba@326: _delta4_index = new IntIntMap(_blossom_num);
deba@326: _delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index);
deba@326: }
deba@326: }
deba@326:
deba@326: void destroyStructures() {
deba@326: _node_num = countNodes(_graph);
deba@326: _blossom_num = _node_num * 3 / 2;
deba@326:
deba@326: if (_matching) {
deba@326: delete _matching;
deba@326: }
deba@326: if (_node_potential) {
deba@326: delete _node_potential;
deba@326: }
deba@326: if (_blossom_set) {
deba@326: delete _blossom_index;
deba@326: delete _blossom_set;
deba@326: delete _blossom_data;
deba@326: }
deba@326:
deba@326: if (_node_index) {
deba@326: delete _node_index;
deba@326: delete _node_heap_index;
deba@326: delete _node_data;
deba@326: }
deba@326:
deba@326: if (_tree_set) {
deba@326: delete _tree_set_index;
deba@326: delete _tree_set;
deba@326: }
deba@326: if (_delta1) {
deba@326: delete _delta1_index;
deba@326: delete _delta1;
deba@326: }
deba@326: if (_delta2) {
deba@326: delete _delta2_index;
deba@326: delete _delta2;
deba@326: }
deba@326: if (_delta3) {
deba@326: delete _delta3_index;
deba@326: delete _delta3;
deba@326: }
deba@326: if (_delta4) {
deba@326: delete _delta4_index;
deba@326: delete _delta4;
deba@326: }
deba@326: }
deba@326:
deba@326: void matchedToEven(int blossom, int tree) {
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326:
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: (*_blossom_data)[blossom].pot -=
deba@326: 2 * (_delta_sum - (*_blossom_data)[blossom].offset);
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326:
deba@326: _blossom_set->increase(n, std::numeric_limits<Value>::max());
deba@326: int ni = (*_node_index)[n];
deba@326:
deba@326: (*_node_data)[ni].heap.clear();
deba@326: (*_node_data)[ni].heap_index.clear();
deba@326:
deba@326: (*_node_data)[ni].pot += _delta_sum - (*_blossom_data)[blossom].offset;
deba@326:
deba@326: _delta1->push(n, (*_node_data)[ni].pot);
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if ((*_blossom_data)[vb].status == EVEN) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) {
deba@326: _delta3->push(e, rw / 2);
deba@326: }
deba@326: } else if ((*_blossom_data)[vb].status == UNMATCHED) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP) {
deba@326: _delta3->push(e, rw);
deba@326: }
deba@326: } else {
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[vi].heap_index.find(tree);
deba@326:
deba@326: if (it != (*_node_data)[vi].heap_index.end()) {
deba@326: if ((*_node_data)[vi].heap[it->second] > rw) {
deba@326: (*_node_data)[vi].heap.replace(it->second, e);
deba@326: (*_node_data)[vi].heap.decrease(e, rw);
deba@326: it->second = e;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[vi].heap.push(e, rw);
deba@326: (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) {
deba@326: _blossom_set->decrease(v, (*_node_data)[vi].heap.prio());
deba@326:
deba@326: if ((*_blossom_data)[vb].status == MATCHED) {
deba@326: if (_delta2->state(vb) != _delta2->IN_HEAP) {
deba@326: _delta2->push(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset){
deba@326: _delta2->decrease(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: (*_blossom_data)[blossom].offset = 0;
deba@326: }
deba@326:
deba@326: void matchedToOdd(int blossom) {
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326: (*_blossom_data)[blossom].offset += _delta_sum;
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: _delta4->push(blossom, (*_blossom_data)[blossom].pot / 2 +
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326: }
deba@326:
deba@326: void evenToMatched(int blossom, int tree) {
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: (*_blossom_data)[blossom].pot += 2 * _delta_sum;
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326: int ni = (*_node_index)[n];
deba@326: (*_node_data)[ni].pot -= _delta_sum;
deba@326:
deba@326: _delta1->erase(n);
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if (vb == blossom) {
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326: } else if ((*_blossom_data)[vb].status == EVEN) {
deba@326:
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326:
deba@326: int vt = _tree_set->find(vb);
deba@326:
deba@326: if (vt != tree) {
deba@326:
deba@326: Arc r = _graph.oppositeArc(e);
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[ni].heap_index.find(vt);
deba@326:
deba@326: if (it != (*_node_data)[ni].heap_index.end()) {
deba@326: if ((*_node_data)[ni].heap[it->second] > rw) {
deba@326: (*_node_data)[ni].heap.replace(it->second, r);
deba@326: (*_node_data)[ni].heap.decrease(r, rw);
deba@326: it->second = r;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[ni].heap.push(r, rw);
deba@326: (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) {
deba@326: _blossom_set->decrease(n, (*_node_data)[ni].heap.prio());
deba@326:
deba@326: if (_delta2->state(blossom) != _delta2->IN_HEAP) {
deba@326: _delta2->push(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: } else if ((*_delta2)[blossom] >
deba@326: _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset){
deba@326: _delta2->decrease(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: } else if ((*_blossom_data)[vb].status == UNMATCHED) {
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326: } else {
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[vi].heap_index.find(tree);
deba@326:
deba@326: if (it != (*_node_data)[vi].heap_index.end()) {
deba@326: (*_node_data)[vi].heap.erase(it->second);
deba@326: (*_node_data)[vi].heap_index.erase(it);
deba@326: if ((*_node_data)[vi].heap.empty()) {
deba@326: _blossom_set->increase(v, std::numeric_limits<Value>::max());
deba@326: } else if ((*_blossom_set)[v] < (*_node_data)[vi].heap.prio()) {
deba@326: _blossom_set->increase(v, (*_node_data)[vi].heap.prio());
deba@326: }
deba@326:
deba@326: if ((*_blossom_data)[vb].status == MATCHED) {
deba@326: if (_blossom_set->classPrio(vb) ==
deba@326: std::numeric_limits<Value>::max()) {
deba@326: _delta2->erase(vb);
deba@326: } else if ((*_delta2)[vb] < _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset) {
deba@326: _delta2->increase(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: void oddToMatched(int blossom) {
deba@326: (*_blossom_data)[blossom].offset -= _delta_sum;
deba@326:
deba@326: if (_blossom_set->classPrio(blossom) !=
deba@326: std::numeric_limits<Value>::max()) {
deba@326: _delta2->push(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326:
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: _delta4->erase(blossom);
deba@326: }
deba@326: }
deba@326:
deba@326: void oddToEven(int blossom, int tree) {
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: _delta4->erase(blossom);
deba@326: (*_blossom_data)[blossom].pot -=
deba@326: 2 * (2 * _delta_sum - (*_blossom_data)[blossom].offset);
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326: int ni = (*_node_index)[n];
deba@326:
deba@326: _blossom_set->increase(n, std::numeric_limits<Value>::max());
deba@326:
deba@326: (*_node_data)[ni].heap.clear();
deba@326: (*_node_data)[ni].heap_index.clear();
deba@326: (*_node_data)[ni].pot +=
deba@326: 2 * _delta_sum - (*_blossom_data)[blossom].offset;
deba@326:
deba@326: _delta1->push(n, (*_node_data)[ni].pot);
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if ((*_blossom_data)[vb].status == EVEN) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) {
deba@326: _delta3->push(e, rw / 2);
deba@326: }
deba@326: } else if ((*_blossom_data)[vb].status == UNMATCHED) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP) {
deba@326: _delta3->push(e, rw);
deba@326: }
deba@326: } else {
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[vi].heap_index.find(tree);
deba@326:
deba@326: if (it != (*_node_data)[vi].heap_index.end()) {
deba@326: if ((*_node_data)[vi].heap[it->second] > rw) {
deba@326: (*_node_data)[vi].heap.replace(it->second, e);
deba@326: (*_node_data)[vi].heap.decrease(e, rw);
deba@326: it->second = e;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[vi].heap.push(e, rw);
deba@326: (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) {
deba@326: _blossom_set->decrease(v, (*_node_data)[vi].heap.prio());
deba@326:
deba@326: if ((*_blossom_data)[vb].status == MATCHED) {
deba@326: if (_delta2->state(vb) != _delta2->IN_HEAP) {
deba@326: _delta2->push(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset) {
deba@326: _delta2->decrease(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: (*_blossom_data)[blossom].offset = 0;
deba@326: }
deba@326:
deba@326:
deba@326: void matchedToUnmatched(int blossom) {
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326: int ni = (*_node_index)[n];
deba@326:
deba@326: _blossom_set->increase(n, std::numeric_limits<Value>::max());
deba@326:
deba@326: (*_node_data)[ni].heap.clear();
deba@326: (*_node_data)[ni].heap_index.clear();
deba@326:
deba@326: for (OutArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.target(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if ((*_blossom_data)[vb].status == EVEN) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP) {
deba@326: _delta3->push(e, rw);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: void unmatchedToMatched(int blossom) {
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326: int ni = (*_node_index)[n];
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if (vb == blossom) {
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326: } else if ((*_blossom_data)[vb].status == EVEN) {
deba@326:
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326:
deba@326: int vt = _tree_set->find(vb);
deba@326:
deba@326: Arc r = _graph.oppositeArc(e);
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[ni].heap_index.find(vt);
deba@326:
deba@326: if (it != (*_node_data)[ni].heap_index.end()) {
deba@326: if ((*_node_data)[ni].heap[it->second] > rw) {
deba@326: (*_node_data)[ni].heap.replace(it->second, r);
deba@326: (*_node_data)[ni].heap.decrease(r, rw);
deba@326: it->second = r;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[ni].heap.push(r, rw);
deba@326: (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) {
deba@326: _blossom_set->decrease(n, (*_node_data)[ni].heap.prio());
deba@326:
deba@326: if (_delta2->state(blossom) != _delta2->IN_HEAP) {
deba@326: _delta2->push(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: } else if ((*_delta2)[blossom] > _blossom_set->classPrio(blossom)-
deba@326: (*_blossom_data)[blossom].offset){
deba@326: _delta2->decrease(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326: }
deba@326:
deba@326: } else if ((*_blossom_data)[vb].status == UNMATCHED) {
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: void alternatePath(int even, int tree) {
deba@326: int odd;
deba@326:
deba@326: evenToMatched(even, tree);
deba@326: (*_blossom_data)[even].status = MATCHED;
deba@326:
deba@326: while ((*_blossom_data)[even].pred != INVALID) {
deba@326: odd = _blossom_set->find(_graph.target((*_blossom_data)[even].pred));
deba@326: (*_blossom_data)[odd].status = MATCHED;
deba@326: oddToMatched(odd);
deba@326: (*_blossom_data)[odd].next = (*_blossom_data)[odd].pred;
deba@326:
deba@326: even = _blossom_set->find(_graph.target((*_blossom_data)[odd].pred));
deba@326: (*_blossom_data)[even].status = MATCHED;
deba@326: evenToMatched(even, tree);
deba@326: (*_blossom_data)[even].next =
deba@326: _graph.oppositeArc((*_blossom_data)[odd].pred);
deba@326: }
deba@326:
deba@326: }
deba@326:
deba@326: void destroyTree(int tree) {
deba@326: for (TreeSet::ItemIt b(*_tree_set, tree); b != INVALID; ++b) {
deba@326: if ((*_blossom_data)[b].status == EVEN) {
deba@326: (*_blossom_data)[b].status = MATCHED;
deba@326: evenToMatched(b, tree);
deba@326: } else if ((*_blossom_data)[b].status == ODD) {
deba@326: (*_blossom_data)[b].status = MATCHED;
deba@326: oddToMatched(b);
deba@326: }
deba@326: }
deba@326: _tree_set->eraseClass(tree);
deba@326: }
deba@326:
deba@326:
deba@326: void unmatchNode(const Node& node) {
deba@326: int blossom = _blossom_set->find(node);
deba@326: int tree = _tree_set->find(blossom);
deba@326:
deba@326: alternatePath(blossom, tree);
deba@326: destroyTree(tree);
deba@326:
deba@326: (*_blossom_data)[blossom].status = UNMATCHED;
deba@326: (*_blossom_data)[blossom].base = node;
deba@326: matchedToUnmatched(blossom);
deba@326: }
deba@326:
deba@326:
deba@327: void augmentOnEdge(const Edge& edge) {
deba@327:
deba@327: int left = _blossom_set->find(_graph.u(edge));
deba@327: int right = _blossom_set->find(_graph.v(edge));
deba@326:
deba@326: if ((*_blossom_data)[left].status == EVEN) {
deba@326: int left_tree = _tree_set->find(left);
deba@326: alternatePath(left, left_tree);
deba@326: destroyTree(left_tree);
deba@326: } else {
deba@326: (*_blossom_data)[left].status = MATCHED;
deba@326: unmatchedToMatched(left);
deba@326: }
deba@326:
deba@326: if ((*_blossom_data)[right].status == EVEN) {
deba@326: int right_tree = _tree_set->find(right);
deba@326: alternatePath(right, right_tree);
deba@326: destroyTree(right_tree);
deba@326: } else {
deba@326: (*_blossom_data)[right].status = MATCHED;
deba@326: unmatchedToMatched(right);
deba@326: }
deba@326:
deba@327: (*_blossom_data)[left].next = _graph.direct(edge, true);
deba@327: (*_blossom_data)[right].next = _graph.direct(edge, false);
deba@326: }
deba@326:
deba@326: void extendOnArc(const Arc& arc) {
deba@326: int base = _blossom_set->find(_graph.target(arc));
deba@326: int tree = _tree_set->find(base);
deba@326:
deba@326: int odd = _blossom_set->find(_graph.source(arc));
deba@326: _tree_set->insert(odd, tree);
deba@326: (*_blossom_data)[odd].status = ODD;
deba@326: matchedToOdd(odd);
deba@326: (*_blossom_data)[odd].pred = arc;
deba@326:
deba@326: int even = _blossom_set->find(_graph.target((*_blossom_data)[odd].next));
deba@326: (*_blossom_data)[even].pred = (*_blossom_data)[even].next;
deba@326: _tree_set->insert(even, tree);
deba@326: (*_blossom_data)[even].status = EVEN;
deba@326: matchedToEven(even, tree);
deba@326: }
deba@326:
deba@327: void shrinkOnEdge(const Edge& edge, int tree) {
deba@326: int nca = -1;
deba@326: std::vector<int> left_path, right_path;
deba@326:
deba@326: {
deba@326: std::set<int> left_set, right_set;
deba@326: int left = _blossom_set->find(_graph.u(edge));
deba@326: left_path.push_back(left);
deba@326: left_set.insert(left);
deba@326:
deba@326: int right = _blossom_set->find(_graph.v(edge));
deba@326: right_path.push_back(right);
deba@326: right_set.insert(right);
deba@326:
deba@326: while (true) {
deba@326:
deba@326: if ((*_blossom_data)[left].pred == INVALID) break;
deba@326:
deba@326: left =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[left].pred));
deba@326: left_path.push_back(left);
deba@326: left =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[left].pred));
deba@326: left_path.push_back(left);
deba@326:
deba@326: left_set.insert(left);
deba@326:
deba@326: if (right_set.find(left) != right_set.end()) {
deba@326: nca = left;
deba@326: break;
deba@326: }
deba@326:
deba@326: if ((*_blossom_data)[right].pred == INVALID) break;
deba@326:
deba@326: right =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[right].pred));
deba@326: right_path.push_back(right);
deba@326: right =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[right].pred));
deba@326: right_path.push_back(right);
deba@326:
deba@326: right_set.insert(right);
deba@326:
deba@326: if (left_set.find(right) != left_set.end()) {
deba@326: nca = right;
deba@326: break;
deba@326: }
deba@326:
deba@326: }
deba@326:
deba@326: if (nca == -1) {
deba@326: if ((*_blossom_data)[left].pred == INVALID) {
deba@326: nca = right;
deba@326: while (left_set.find(nca) == left_set.end()) {
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: right_path.push_back(nca);
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: right_path.push_back(nca);
deba@326: }
deba@326: } else {
deba@326: nca = left;
deba@326: while (right_set.find(nca) == right_set.end()) {
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: left_path.push_back(nca);
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: left_path.push_back(nca);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: std::vector<int> subblossoms;
deba@326: Arc prev;
deba@326:
deba@326: prev = _graph.direct(edge, true);
deba@326: for (int i = 0; left_path[i] != nca; i += 2) {
deba@326: subblossoms.push_back(left_path[i]);
deba@326: (*_blossom_data)[left_path[i]].next = prev;
deba@326: _tree_set->erase(left_path[i]);
deba@326:
deba@326: subblossoms.push_back(left_path[i + 1]);
deba@326: (*_blossom_data)[left_path[i + 1]].status = EVEN;
deba@326: oddToEven(left_path[i + 1], tree);
deba@326: _tree_set->erase(left_path[i + 1]);
deba@326: prev = _graph.oppositeArc((*_blossom_data)[left_path[i + 1]].pred);
deba@326: }
deba@326:
deba@326: int k = 0;
deba@326: while (right_path[k] != nca) ++k;
deba@326:
deba@326: subblossoms.push_back(nca);
deba@326: (*_blossom_data)[nca].next = prev;
deba@326:
deba@326: for (int i = k - 2; i >= 0; i -= 2) {
deba@326: subblossoms.push_back(right_path[i + 1]);
deba@326: (*_blossom_data)[right_path[i + 1]].status = EVEN;
deba@326: oddToEven(right_path[i + 1], tree);
deba@326: _tree_set->erase(right_path[i + 1]);
deba@326:
deba@326: (*_blossom_data)[right_path[i + 1]].next =
deba@326: (*_blossom_data)[right_path[i + 1]].pred;
deba@326:
deba@326: subblossoms.push_back(right_path[i]);
deba@326: _tree_set->erase(right_path[i]);
deba@326: }
deba@326:
deba@326: int surface =
deba@326: _blossom_set->join(subblossoms.begin(), subblossoms.end());
deba@326:
deba@326: for (int i = 0; i < int(subblossoms.size()); ++i) {
deba@326: if (!_blossom_set->trivial(subblossoms[i])) {
deba@326: (*_blossom_data)[subblossoms[i]].pot += 2 * _delta_sum;
deba@326: }
deba@326: (*_blossom_data)[subblossoms[i]].status = MATCHED;
deba@326: }
deba@326:
deba@326: (*_blossom_data)[surface].pot = -2 * _delta_sum;
deba@326: (*_blossom_data)[surface].offset = 0;
deba@326: (*_blossom_data)[surface].status = EVEN;
deba@326: (*_blossom_data)[surface].pred = (*_blossom_data)[nca].pred;
deba@326: (*_blossom_data)[surface].next = (*_blossom_data)[nca].pred;
deba@326:
deba@326: _tree_set->insert(surface, tree);
deba@326: _tree_set->erase(nca);
deba@326: }
deba@326:
deba@326: void splitBlossom(int blossom) {
deba@326: Arc next = (*_blossom_data)[blossom].next;
deba@326: Arc pred = (*_blossom_data)[blossom].pred;
deba@326:
deba@326: int tree = _tree_set->find(blossom);
deba@326:
deba@326: (*_blossom_data)[blossom].status = MATCHED;
deba@326: oddToMatched(blossom);
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326:
deba@326: std::vector<int> subblossoms;
deba@326: _blossom_set->split(blossom, std::back_inserter(subblossoms));
deba@326:
deba@326: Value offset = (*_blossom_data)[blossom].offset;
deba@326: int b = _blossom_set->find(_graph.source(pred));
deba@326: int d = _blossom_set->find(_graph.source(next));
deba@326:
deba@326: int ib = -1, id = -1;
deba@326: for (int i = 0; i < int(subblossoms.size()); ++i) {
deba@326: if (subblossoms[i] == b) ib = i;
deba@326: if (subblossoms[i] == d) id = i;
deba@326:
deba@326: (*_blossom_data)[subblossoms[i]].offset = offset;
deba@326: if (!_blossom_set->trivial(subblossoms[i])) {
deba@326: (*_blossom_data)[subblossoms[i]].pot -= 2 * offset;
deba@326: }
deba@326: if (_blossom_set->classPrio(subblossoms[i]) !=
deba@326: std::numeric_limits<Value>::max()) {
deba@326: _delta2->push(subblossoms[i],
deba@326: _blossom_set->classPrio(subblossoms[i]) -
deba@326: (*_blossom_data)[subblossoms[i]].offset);
deba@326: }
deba@326: }
deba@326:
deba@326: if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) {
deba@326: for (int i = (id + 1) % subblossoms.size();
deba@326: i != ib; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: (*_blossom_data)[sb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326: }
deba@326:
deba@326: for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: int ub = subblossoms[(i + 2) % subblossoms.size()];
deba@326:
deba@326: (*_blossom_data)[sb].status = ODD;
deba@326: matchedToOdd(sb);
deba@326: _tree_set->insert(sb, tree);
deba@326: (*_blossom_data)[sb].pred = pred;
deba@326: (*_blossom_data)[sb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326:
deba@326: pred = (*_blossom_data)[ub].next;
deba@326:
deba@326: (*_blossom_data)[tb].status = EVEN;
deba@326: matchedToEven(tb, tree);
deba@326: _tree_set->insert(tb, tree);
deba@326: (*_blossom_data)[tb].pred = (*_blossom_data)[tb].next;
deba@326: }
deba@326:
deba@326: (*_blossom_data)[subblossoms[id]].status = ODD;
deba@326: matchedToOdd(subblossoms[id]);
deba@326: _tree_set->insert(subblossoms[id], tree);
deba@326: (*_blossom_data)[subblossoms[id]].next = next;
deba@326: (*_blossom_data)[subblossoms[id]].pred = pred;
deba@326:
deba@326: } else {
deba@326:
deba@326: for (int i = (ib + 1) % subblossoms.size();
deba@326: i != id; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: (*_blossom_data)[sb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326: }
deba@326:
deba@326: for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: int ub = subblossoms[(i + 2) % subblossoms.size()];
deba@326:
deba@326: (*_blossom_data)[sb].status = ODD;
deba@326: matchedToOdd(sb);
deba@326: _tree_set->insert(sb, tree);
deba@326: (*_blossom_data)[sb].next = next;
deba@326: (*_blossom_data)[sb].pred =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326:
deba@326: (*_blossom_data)[tb].status = EVEN;
deba@326: matchedToEven(tb, tree);
deba@326: _tree_set->insert(tb, tree);
deba@326: (*_blossom_data)[tb].pred =
deba@326: (*_blossom_data)[tb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[ub].next);
deba@326: next = (*_blossom_data)[ub].next;
deba@326: }
deba@326:
deba@326: (*_blossom_data)[subblossoms[ib]].status = ODD;
deba@326: matchedToOdd(subblossoms[ib]);
deba@326: _tree_set->insert(subblossoms[ib], tree);
deba@326: (*_blossom_data)[subblossoms[ib]].next = next;
deba@326: (*_blossom_data)[subblossoms[ib]].pred = pred;
deba@326: }
deba@326: _tree_set->erase(blossom);
deba@326: }
deba@326:
deba@326: void extractBlossom(int blossom, const Node& base, const Arc& matching) {
deba@326: if (_blossom_set->trivial(blossom)) {
deba@326: int bi = (*_node_index)[base];
deba@326: Value pot = (*_node_data)[bi].pot;
deba@326:
deba@326: _matching->set(base, matching);
deba@326: _blossom_node_list.push_back(base);
deba@326: _node_potential->set(base, pot);
deba@326: } else {
deba@326:
deba@326: Value pot = (*_blossom_data)[blossom].pot;
deba@326: int bn = _blossom_node_list.size();
deba@326:
deba@326: std::vector<int> subblossoms;
deba@326: _blossom_set->split(blossom, std::back_inserter(subblossoms));
deba@326: int b = _blossom_set->find(base);
deba@326: int ib = -1;
deba@326: for (int i = 0; i < int(subblossoms.size()); ++i) {
deba@326: if (subblossoms[i] == b) { ib = i; break; }
deba@326: }
deba@326:
deba@326: for (int i = 1; i < int(subblossoms.size()); i += 2) {
deba@326: int sb = subblossoms[(ib + i) % subblossoms.size()];
deba@326: int tb = subblossoms[(ib + i + 1) % subblossoms.size()];
deba@326:
deba@326: Arc m = (*_blossom_data)[tb].next;
deba@326: extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m));
deba@326: extractBlossom(tb, _graph.source(m), m);
deba@326: }
deba@326: extractBlossom(subblossoms[ib], base, matching);
deba@326:
deba@326: int en = _blossom_node_list.size();
deba@326:
deba@326: _blossom_potential.push_back(BlossomVariable(bn, en, pot));
deba@326: }
deba@326: }
deba@326:
deba@326: void extractMatching() {
deba@326: std::vector<int> blossoms;
deba@326: for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) {
deba@326: blossoms.push_back(c);
deba@326: }
deba@326:
deba@326: for (int i = 0; i < int(blossoms.size()); ++i) {
deba@326: if ((*_blossom_data)[blossoms[i]].status == MATCHED) {
deba@326:
deba@326: Value offset = (*_blossom_data)[blossoms[i]].offset;
deba@326: (*_blossom_data)[blossoms[i]].pot += 2 * offset;
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]);
deba@326: n != INVALID; ++n) {
deba@326: (*_node_data)[(*_node_index)[n]].pot -= offset;
deba@326: }
deba@326:
deba@326: Arc matching = (*_blossom_data)[blossoms[i]].next;
deba@326: Node base = _graph.source(matching);
deba@326: extractBlossom(blossoms[i], base, matching);
deba@326: } else {
deba@326: Node base = (*_blossom_data)[blossoms[i]].base;
deba@326: extractBlossom(blossoms[i], base, INVALID);
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: public:
deba@326:
deba@326: /// \brief Constructor
deba@326: ///
deba@326: /// Constructor.
deba@326: MaxWeightedMatching(const Graph& graph, const WeightMap& weight)
deba@326: : _graph(graph), _weight(weight), _matching(0),
deba@326: _node_potential(0), _blossom_potential(), _blossom_node_list(),
deba@326: _node_num(0), _blossom_num(0),
deba@326:
deba@326: _blossom_index(0), _blossom_set(0), _blossom_data(0),
deba@326: _node_index(0), _node_heap_index(0), _node_data(0),
deba@326: _tree_set_index(0), _tree_set(0),
deba@326:
deba@326: _delta1_index(0), _delta1(0),
deba@326: _delta2_index(0), _delta2(0),
deba@326: _delta3_index(0), _delta3(0),
deba@326: _delta4_index(0), _delta4(0),
deba@326:
deba@326: _delta_sum() {}
deba@326:
deba@326: ~MaxWeightedMatching() {
deba@326: destroyStructures();
deba@326: }
deba@326:
deba@326: /// \name Execution control
alpar@330: /// The simplest way to execute the algorithm is to use the
deba@326: /// \c run() member function.
deba@326:
deba@326: ///@{
deba@326:
deba@326: /// \brief Initialize the algorithm
deba@326: ///
deba@326: /// Initialize the algorithm
deba@326: void init() {
deba@326: createStructures();
deba@326:
deba@326: for (ArcIt e(_graph); e != INVALID; ++e) {
deba@327: _node_heap_index->set(e, BinHeap<Value, IntArcMap>::PRE_HEAP);
deba@326: }
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: _delta1_index->set(n, _delta1->PRE_HEAP);
deba@326: }
deba@326: for (EdgeIt e(_graph); e != INVALID; ++e) {
deba@326: _delta3_index->set(e, _delta3->PRE_HEAP);
deba@326: }
deba@326: for (int i = 0; i < _blossom_num; ++i) {
deba@326: _delta2_index->set(i, _delta2->PRE_HEAP);
deba@326: _delta4_index->set(i, _delta4->PRE_HEAP);
deba@326: }
deba@326:
deba@326: int index = 0;
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: Value max = 0;
deba@326: for (OutArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: if (_graph.target(e) == n) continue;
deba@326: if ((dualScale * _weight[e]) / 2 > max) {
deba@326: max = (dualScale * _weight[e]) / 2;
deba@326: }
deba@326: }
deba@326: _node_index->set(n, index);
deba@326: (*_node_data)[index].pot = max;
deba@326: _delta1->push(n, max);
deba@326: int blossom =
deba@326: _blossom_set->insert(n, std::numeric_limits<Value>::max());
deba@326:
deba@326: _tree_set->insert(blossom);
deba@326:
deba@326: (*_blossom_data)[blossom].status = EVEN;
deba@326: (*_blossom_data)[blossom].pred = INVALID;
deba@326: (*_blossom_data)[blossom].next = INVALID;
deba@326: (*_blossom_data)[blossom].pot = 0;
deba@326: (*_blossom_data)[blossom].offset = 0;
deba@326: ++index;
deba@326: }
deba@326: for (EdgeIt e(_graph); e != INVALID; ++e) {
deba@326: int si = (*_node_index)[_graph.u(e)];
deba@326: int ti = (*_node_index)[_graph.v(e)];
deba@326: if (_graph.u(e) != _graph.v(e)) {
deba@326: _delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot -
deba@326: dualScale * _weight[e]) / 2);
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: /// \brief Starts the algorithm
deba@326: ///
deba@326: /// Starts the algorithm
deba@326: void start() {
deba@326: enum OpType {
deba@326: D1, D2, D3, D4
deba@326: };
deba@326:
deba@326: int unmatched = _node_num;
deba@326: while (unmatched > 0) {
deba@326: Value d1 = !_delta1->empty() ?
deba@326: _delta1->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: Value d2 = !_delta2->empty() ?
deba@326: _delta2->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: Value d3 = !_delta3->empty() ?
deba@326: _delta3->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: Value d4 = !_delta4->empty() ?
deba@326: _delta4->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: _delta_sum = d1; OpType ot = D1;
deba@326: if (d2 < _delta_sum) { _delta_sum = d2; ot = D2; }
deba@326: if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; }
deba@326: if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; }
deba@326:
deba@326:
deba@326: switch (ot) {
deba@326: case D1:
deba@326: {
deba@326: Node n = _delta1->top();
deba@326: unmatchNode(n);
deba@326: --unmatched;
deba@326: }
deba@326: break;
deba@326: case D2:
deba@326: {
deba@326: int blossom = _delta2->top();
deba@326: Node n = _blossom_set->classTop(blossom);
deba@326: Arc e = (*_node_data)[(*_node_index)[n]].heap.top();
deba@326: extendOnArc(e);
deba@326: }
deba@326: break;
deba@326: case D3:
deba@326: {
deba@326: Edge e = _delta3->top();
deba@326:
deba@326: int left_blossom = _blossom_set->find(_graph.u(e));
deba@326: int right_blossom = _blossom_set->find(_graph.v(e));
deba@326:
deba@326: if (left_blossom == right_blossom) {
deba@326: _delta3->pop();
deba@326: } else {
deba@326: int left_tree;
deba@326: if ((*_blossom_data)[left_blossom].status == EVEN) {
deba@326: left_tree = _tree_set->find(left_blossom);
deba@326: } else {
deba@326: left_tree = -1;
deba@326: ++unmatched;
deba@326: }
deba@326: int right_tree;
deba@326: if ((*_blossom_data)[right_blossom].status == EVEN) {
deba@326: right_tree = _tree_set->find(right_blossom);
deba@326: } else {
deba@326: right_tree = -1;
deba@326: ++unmatched;
deba@326: }
deba@326:
deba@326: if (left_tree == right_tree) {
deba@327: shrinkOnEdge(e, left_tree);
deba@326: } else {
deba@327: augmentOnEdge(e);
deba@326: unmatched -= 2;
deba@326: }
deba@326: }
deba@326: } break;
deba@326: case D4:
deba@326: splitBlossom(_delta4->top());
deba@326: break;
deba@326: }
deba@326: }
deba@326: extractMatching();
deba@326: }
deba@326:
deba@326: /// \brief Runs %MaxWeightedMatching algorithm.
deba@326: ///
deba@326: /// This method runs the %MaxWeightedMatching algorithm.
deba@326: ///
deba@326: /// \note mwm.run() is just a shortcut of the following code.
deba@326: /// \code
deba@326: /// mwm.init();
deba@326: /// mwm.start();
deba@326: /// \endcode
deba@326: void run() {
deba@326: init();
deba@326: start();
deba@326: }
deba@326:
deba@326: /// @}
deba@326:
deba@326: /// \name Primal solution
alpar@330: /// Functions to get the primal solution, ie. the matching.
deba@326:
deba@326: /// @{
deba@326:
alpar@330: /// \brief Returns the weight of the matching.
deba@326: ///
alpar@330: /// Returns the weight of the matching.
deba@326: Value matchingValue() const {
deba@326: Value sum = 0;
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: if ((*_matching)[n] != INVALID) {
deba@326: sum += _weight[(*_matching)[n]];
deba@326: }
deba@326: }
deba@326: return sum /= 2;
deba@326: }
deba@326:
deba@327: /// \brief Returns the cardinality of the matching.
deba@326: ///
deba@327: /// Returns the cardinality of the matching.
deba@327: int matchingSize() const {
deba@327: int num = 0;
deba@327: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@327: if ((*_matching)[n] != INVALID) {
deba@327: ++num;
deba@327: }
deba@327: }
deba@327: return num /= 2;
deba@327: }
deba@327:
deba@327: /// \brief Returns true when the edge is in the matching.
deba@327: ///
deba@327: /// Returns true when the edge is in the matching.
deba@327: bool matching(const Edge& edge) const {
deba@327: return edge == (*_matching)[_graph.u(edge)];
deba@326: }
deba@326:
deba@326: /// \brief Returns the incident matching arc.
deba@326: ///
deba@326: /// Returns the incident matching arc from given node. If the
deba@326: /// node is not matched then it gives back \c INVALID.
deba@326: Arc matching(const Node& node) const {
deba@326: return (*_matching)[node];
deba@326: }
deba@326:
deba@326: /// \brief Returns the mate of the node.
deba@326: ///
deba@326: /// Returns the adjancent node in a mathcing arc. If the node is
deba@326: /// not matched then it gives back \c INVALID.
deba@326: Node mate(const Node& node) const {
deba@326: return (*_matching)[node] != INVALID ?
deba@326: _graph.target((*_matching)[node]) : INVALID;
deba@326: }
deba@326:
deba@326: /// @}
deba@326:
deba@326: /// \name Dual solution
alpar@330: /// Functions to get the dual solution.
deba@326:
deba@326: /// @{
deba@326:
deba@326: /// \brief Returns the value of the dual solution.
deba@326: ///
deba@326: /// Returns the value of the dual solution. It should be equal to
deba@326: /// the primal value scaled by \ref dualScale "dual scale".
deba@326: Value dualValue() const {
deba@326: Value sum = 0;
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: sum += nodeValue(n);
deba@326: }
deba@326: for (int i = 0; i < blossomNum(); ++i) {
deba@326: sum += blossomValue(i) * (blossomSize(i) / 2);
deba@326: }
deba@326: return sum;
deba@326: }
deba@326:
deba@326: /// \brief Returns the value of the node.
deba@326: ///
deba@326: /// Returns the the value of the node.
deba@326: Value nodeValue(const Node& n) const {
deba@326: return (*_node_potential)[n];
deba@326: }
deba@326:
deba@326: /// \brief Returns the number of the blossoms in the basis.
deba@326: ///
deba@326: /// Returns the number of the blossoms in the basis.
deba@326: /// \see BlossomIt
deba@326: int blossomNum() const {
deba@326: return _blossom_potential.size();
deba@326: }
deba@326:
deba@326:
deba@326: /// \brief Returns the number of the nodes in the blossom.
deba@326: ///
deba@326: /// Returns the number of the nodes in the blossom.
deba@326: int blossomSize(int k) const {
deba@326: return _blossom_potential[k].end - _blossom_potential[k].begin;
deba@326: }
deba@326:
deba@326: /// \brief Returns the value of the blossom.
deba@326: ///
deba@326: /// Returns the the value of the blossom.
deba@326: /// \see BlossomIt
deba@326: Value blossomValue(int k) const {
deba@326: return _blossom_potential[k].value;
deba@326: }
deba@326:
alpar@330: /// \brief Iterator for obtaining the nodes of the blossom.
deba@326: ///
alpar@330: /// Iterator for obtaining the nodes of the blossom. This class
alpar@330: /// provides a common lemon style iterator for listing a
deba@326: /// subset of the nodes.
deba@326: class BlossomIt {
deba@326: public:
deba@326:
deba@326: /// \brief Constructor.
deba@326: ///
alpar@330: /// Constructor to get the nodes of the variable.
deba@326: BlossomIt(const MaxWeightedMatching& algorithm, int variable)
deba@326: : _algorithm(&algorithm)
deba@326: {
deba@326: _index = _algorithm->_blossom_potential[variable].begin;
deba@326: _last = _algorithm->_blossom_potential[variable].end;
deba@326: }
deba@326:
deba@326: /// \brief Conversion to node.
deba@326: ///
deba@326: /// Conversion to node.
deba@326: operator Node() const {
deba@327: return _algorithm->_blossom_node_list[_index];
deba@326: }
deba@326:
deba@326: /// \brief Increment operator.
deba@326: ///
deba@326: /// Increment operator.
deba@326: BlossomIt& operator++() {
deba@326: ++_index;
deba@326: return *this;
deba@326: }
deba@326:
deba@327: /// \brief Validity checking
deba@327: ///
deba@327: /// Checks whether the iterator is invalid.
deba@327: bool operator==(Invalid) const { return _index == _last; }
deba@327:
deba@327: /// \brief Validity checking
deba@327: ///
deba@327: /// Checks whether the iterator is valid.
deba@327: bool operator!=(Invalid) const { return _index != _last; }
deba@326:
deba@326: private:
deba@326: const MaxWeightedMatching* _algorithm;
deba@326: int _last;
deba@326: int _index;
deba@326: };
deba@326:
deba@326: /// @}
deba@326:
deba@326: };
deba@326:
deba@326: /// \ingroup matching
deba@326: ///
deba@326: /// \brief Weighted perfect matching in general graphs
deba@326: ///
deba@326: /// This class provides an efficient implementation of Edmond's
deba@327: /// maximum weighted perfect matching algorithm. The implementation
deba@326: /// is based on extensive use of priority queues and provides
deba@326: /// \f$O(nm\log(n))\f$ time complexity.
deba@326: ///
deba@326: /// The maximum weighted matching problem is to find undirected
deba@327: /// edges in the graph with maximum overall weight and no two of
deba@327: /// them shares their ends and covers all nodes. The problem can be
deba@327: /// formulated with the following linear program.
deba@326: /// \f[ \sum_{e \in \delta(u)}x_e = 1 \quad \forall u\in V\f]
deba@327: /** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2}
deba@327: \quad \forall B\in\mathcal{O}\f] */
deba@326: /// \f[x_e \ge 0\quad \forall e\in E\f]
deba@326: /// \f[\max \sum_{e\in E}x_ew_e\f]
deba@327: /// where \f$\delta(X)\f$ is the set of edges incident to a node in
deba@327: /// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in
deba@327: /// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality
deba@327: /// subsets of the nodes.
deba@326: ///
deba@326: /// The algorithm calculates an optimal matching and a proof of the
deba@326: /// optimality. The solution of the dual problem can be used to check
deba@327: /// the result of the algorithm. The dual linear problem is the
deba@327: /** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}z_B \ge
deba@327: w_{uv} \quad \forall uv\in E\f] */
deba@326: /// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f]
deba@327: /** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}}
deba@327: \frac{\vert B \vert - 1}{2}z_B\f] */
deba@326: ///
deba@326: /// The algorithm can be executed with \c run() or the \c init() and
deba@326: /// then the \c start() member functions. After it the matching can
deba@326: /// be asked with \c matching() or mate() functions. The dual
deba@326: /// solution can be get with \c nodeValue(), \c blossomNum() and \c
deba@326: /// blossomValue() members and \ref MaxWeightedMatching::BlossomIt
deba@326: /// "BlossomIt" nested class which is able to iterate on the nodes
deba@326: /// of a blossom. If the value type is integral then the dual
deba@326: /// solution is multiplied by \ref MaxWeightedMatching::dualScale "4".
deba@326: template <typename _Graph,
deba@326: typename _WeightMap = typename _Graph::template EdgeMap<int> >
deba@326: class MaxWeightedPerfectMatching {
deba@326: public:
deba@326:
deba@326: typedef _Graph Graph;
deba@326: typedef _WeightMap WeightMap;
deba@326: typedef typename WeightMap::Value Value;
deba@326:
deba@326: /// \brief Scaling factor for dual solution
deba@326: ///
deba@326: /// Scaling factor for dual solution, it is equal to 4 or 1
deba@326: /// according to the value type.
deba@326: static const int dualScale =
deba@326: std::numeric_limits<Value>::is_integer ? 4 : 1;
deba@326:
deba@326: typedef typename Graph::template NodeMap<typename Graph::Arc>
deba@326: MatchingMap;
deba@326:
deba@326: private:
deba@326:
deba@326: TEMPLATE_GRAPH_TYPEDEFS(Graph);
deba@326:
deba@326: typedef typename Graph::template NodeMap<Value> NodePotential;
deba@326: typedef std::vector<Node> BlossomNodeList;
deba@326:
deba@326: struct BlossomVariable {
deba@326: int begin, end;
deba@326: Value value;
deba@326:
deba@326: BlossomVariable(int _begin, int _end, Value _value)
deba@326: : begin(_begin), end(_end), value(_value) {}
deba@326:
deba@326: };
deba@326:
deba@326: typedef std::vector<BlossomVariable> BlossomPotential;
deba@326:
deba@326: const Graph& _graph;
deba@326: const WeightMap& _weight;
deba@326:
deba@326: MatchingMap* _matching;
deba@326:
deba@326: NodePotential* _node_potential;
deba@326:
deba@326: BlossomPotential _blossom_potential;
deba@326: BlossomNodeList _blossom_node_list;
deba@326:
deba@326: int _node_num;
deba@326: int _blossom_num;
deba@326:
deba@326: typedef RangeMap<int> IntIntMap;
deba@326:
deba@326: enum Status {
deba@326: EVEN = -1, MATCHED = 0, ODD = 1
deba@326: };
deba@326:
deba@327: typedef HeapUnionFind<Value, IntNodeMap> BlossomSet;
deba@326: struct BlossomData {
deba@326: int tree;
deba@326: Status status;
deba@326: Arc pred, next;
deba@326: Value pot, offset;
deba@326: };
deba@326:
deba@327: IntNodeMap *_blossom_index;
deba@326: BlossomSet *_blossom_set;
deba@326: RangeMap<BlossomData>* _blossom_data;
deba@326:
deba@327: IntNodeMap *_node_index;
deba@327: IntArcMap *_node_heap_index;
deba@326:
deba@326: struct NodeData {
deba@326:
deba@327: NodeData(IntArcMap& node_heap_index)
deba@326: : heap(node_heap_index) {}
deba@326:
deba@326: int blossom;
deba@326: Value pot;
deba@327: BinHeap<Value, IntArcMap> heap;
deba@326: std::map<int, Arc> heap_index;
deba@326:
deba@326: int tree;
deba@326: };
deba@326:
deba@326: RangeMap<NodeData>* _node_data;
deba@326:
deba@326: typedef ExtendFindEnum<IntIntMap> TreeSet;
deba@326:
deba@326: IntIntMap *_tree_set_index;
deba@326: TreeSet *_tree_set;
deba@326:
deba@326: IntIntMap *_delta2_index;
deba@326: BinHeap<Value, IntIntMap> *_delta2;
deba@326:
deba@327: IntEdgeMap *_delta3_index;
deba@327: BinHeap<Value, IntEdgeMap> *_delta3;
deba@326:
deba@326: IntIntMap *_delta4_index;
deba@326: BinHeap<Value, IntIntMap> *_delta4;
deba@326:
deba@326: Value _delta_sum;
deba@326:
deba@326: void createStructures() {
deba@326: _node_num = countNodes(_graph);
deba@326: _blossom_num = _node_num * 3 / 2;
deba@326:
deba@326: if (!_matching) {
deba@326: _matching = new MatchingMap(_graph);
deba@326: }
deba@326: if (!_node_potential) {
deba@326: _node_potential = new NodePotential(_graph);
deba@326: }
deba@326: if (!_blossom_set) {
deba@327: _blossom_index = new IntNodeMap(_graph);
deba@326: _blossom_set = new BlossomSet(*_blossom_index);
deba@326: _blossom_data = new RangeMap<BlossomData>(_blossom_num);
deba@326: }
deba@326:
deba@326: if (!_node_index) {
deba@327: _node_index = new IntNodeMap(_graph);
deba@327: _node_heap_index = new IntArcMap(_graph);
deba@326: _node_data = new RangeMap<NodeData>(_node_num,
deba@327: NodeData(*_node_heap_index));
deba@326: }
deba@326:
deba@326: if (!_tree_set) {
deba@326: _tree_set_index = new IntIntMap(_blossom_num);
deba@326: _tree_set = new TreeSet(*_tree_set_index);
deba@326: }
deba@326: if (!_delta2) {
deba@326: _delta2_index = new IntIntMap(_blossom_num);
deba@326: _delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index);
deba@326: }
deba@326: if (!_delta3) {
deba@327: _delta3_index = new IntEdgeMap(_graph);
deba@327: _delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index);
deba@326: }
deba@326: if (!_delta4) {
deba@326: _delta4_index = new IntIntMap(_blossom_num);
deba@326: _delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index);
deba@326: }
deba@326: }
deba@326:
deba@326: void destroyStructures() {
deba@326: _node_num = countNodes(_graph);
deba@326: _blossom_num = _node_num * 3 / 2;
deba@326:
deba@326: if (_matching) {
deba@326: delete _matching;
deba@326: }
deba@326: if (_node_potential) {
deba@326: delete _node_potential;
deba@326: }
deba@326: if (_blossom_set) {
deba@326: delete _blossom_index;
deba@326: delete _blossom_set;
deba@326: delete _blossom_data;
deba@326: }
deba@326:
deba@326: if (_node_index) {
deba@326: delete _node_index;
deba@326: delete _node_heap_index;
deba@326: delete _node_data;
deba@326: }
deba@326:
deba@326: if (_tree_set) {
deba@326: delete _tree_set_index;
deba@326: delete _tree_set;
deba@326: }
deba@326: if (_delta2) {
deba@326: delete _delta2_index;
deba@326: delete _delta2;
deba@326: }
deba@326: if (_delta3) {
deba@326: delete _delta3_index;
deba@326: delete _delta3;
deba@326: }
deba@326: if (_delta4) {
deba@326: delete _delta4_index;
deba@326: delete _delta4;
deba@326: }
deba@326: }
deba@326:
deba@326: void matchedToEven(int blossom, int tree) {
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326:
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: (*_blossom_data)[blossom].pot -=
deba@326: 2 * (_delta_sum - (*_blossom_data)[blossom].offset);
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326:
deba@326: _blossom_set->increase(n, std::numeric_limits<Value>::max());
deba@326: int ni = (*_node_index)[n];
deba@326:
deba@326: (*_node_data)[ni].heap.clear();
deba@326: (*_node_data)[ni].heap_index.clear();
deba@326:
deba@326: (*_node_data)[ni].pot += _delta_sum - (*_blossom_data)[blossom].offset;
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if ((*_blossom_data)[vb].status == EVEN) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) {
deba@326: _delta3->push(e, rw / 2);
deba@326: }
deba@326: } else {
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[vi].heap_index.find(tree);
deba@326:
deba@326: if (it != (*_node_data)[vi].heap_index.end()) {
deba@326: if ((*_node_data)[vi].heap[it->second] > rw) {
deba@326: (*_node_data)[vi].heap.replace(it->second, e);
deba@326: (*_node_data)[vi].heap.decrease(e, rw);
deba@326: it->second = e;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[vi].heap.push(e, rw);
deba@326: (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) {
deba@326: _blossom_set->decrease(v, (*_node_data)[vi].heap.prio());
deba@326:
deba@326: if ((*_blossom_data)[vb].status == MATCHED) {
deba@326: if (_delta2->state(vb) != _delta2->IN_HEAP) {
deba@326: _delta2->push(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset){
deba@326: _delta2->decrease(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: (*_blossom_data)[blossom].offset = 0;
deba@326: }
deba@326:
deba@326: void matchedToOdd(int blossom) {
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326: (*_blossom_data)[blossom].offset += _delta_sum;
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: _delta4->push(blossom, (*_blossom_data)[blossom].pot / 2 +
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326: }
deba@326:
deba@326: void evenToMatched(int blossom, int tree) {
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: (*_blossom_data)[blossom].pot += 2 * _delta_sum;
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326: int ni = (*_node_index)[n];
deba@326: (*_node_data)[ni].pot -= _delta_sum;
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if (vb == blossom) {
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326: } else if ((*_blossom_data)[vb].status == EVEN) {
deba@326:
deba@326: if (_delta3->state(e) == _delta3->IN_HEAP) {
deba@326: _delta3->erase(e);
deba@326: }
deba@326:
deba@326: int vt = _tree_set->find(vb);
deba@326:
deba@326: if (vt != tree) {
deba@326:
deba@326: Arc r = _graph.oppositeArc(e);
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[ni].heap_index.find(vt);
deba@326:
deba@326: if (it != (*_node_data)[ni].heap_index.end()) {
deba@326: if ((*_node_data)[ni].heap[it->second] > rw) {
deba@326: (*_node_data)[ni].heap.replace(it->second, r);
deba@326: (*_node_data)[ni].heap.decrease(r, rw);
deba@326: it->second = r;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[ni].heap.push(r, rw);
deba@326: (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) {
deba@326: _blossom_set->decrease(n, (*_node_data)[ni].heap.prio());
deba@326:
deba@326: if (_delta2->state(blossom) != _delta2->IN_HEAP) {
deba@326: _delta2->push(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: } else if ((*_delta2)[blossom] >
deba@326: _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset){
deba@326: _delta2->decrease(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: } else {
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[vi].heap_index.find(tree);
deba@326:
deba@326: if (it != (*_node_data)[vi].heap_index.end()) {
deba@326: (*_node_data)[vi].heap.erase(it->second);
deba@326: (*_node_data)[vi].heap_index.erase(it);
deba@326: if ((*_node_data)[vi].heap.empty()) {
deba@326: _blossom_set->increase(v, std::numeric_limits<Value>::max());
deba@326: } else if ((*_blossom_set)[v] < (*_node_data)[vi].heap.prio()) {
deba@326: _blossom_set->increase(v, (*_node_data)[vi].heap.prio());
deba@326: }
deba@326:
deba@326: if ((*_blossom_data)[vb].status == MATCHED) {
deba@326: if (_blossom_set->classPrio(vb) ==
deba@326: std::numeric_limits<Value>::max()) {
deba@326: _delta2->erase(vb);
deba@326: } else if ((*_delta2)[vb] < _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset) {
deba@326: _delta2->increase(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: void oddToMatched(int blossom) {
deba@326: (*_blossom_data)[blossom].offset -= _delta_sum;
deba@326:
deba@326: if (_blossom_set->classPrio(blossom) !=
deba@326: std::numeric_limits<Value>::max()) {
deba@326: _delta2->push(blossom, _blossom_set->classPrio(blossom) -
deba@326: (*_blossom_data)[blossom].offset);
deba@326: }
deba@326:
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: _delta4->erase(blossom);
deba@326: }
deba@326: }
deba@326:
deba@326: void oddToEven(int blossom, int tree) {
deba@326: if (!_blossom_set->trivial(blossom)) {
deba@326: _delta4->erase(blossom);
deba@326: (*_blossom_data)[blossom].pot -=
deba@326: 2 * (2 * _delta_sum - (*_blossom_data)[blossom].offset);
deba@326: }
deba@326:
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
deba@326: n != INVALID; ++n) {
deba@326: int ni = (*_node_index)[n];
deba@326:
deba@326: _blossom_set->increase(n, std::numeric_limits<Value>::max());
deba@326:
deba@326: (*_node_data)[ni].heap.clear();
deba@326: (*_node_data)[ni].heap_index.clear();
deba@326: (*_node_data)[ni].pot +=
deba@326: 2 * _delta_sum - (*_blossom_data)[blossom].offset;
deba@326:
deba@326: for (InArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: Node v = _graph.source(e);
deba@326: int vb = _blossom_set->find(v);
deba@326: int vi = (*_node_index)[v];
deba@326:
deba@326: Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot -
deba@326: dualScale * _weight[e];
deba@326:
deba@326: if ((*_blossom_data)[vb].status == EVEN) {
deba@326: if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) {
deba@326: _delta3->push(e, rw / 2);
deba@326: }
deba@326: } else {
deba@326:
deba@326: typename std::map<int, Arc>::iterator it =
deba@326: (*_node_data)[vi].heap_index.find(tree);
deba@326:
deba@326: if (it != (*_node_data)[vi].heap_index.end()) {
deba@326: if ((*_node_data)[vi].heap[it->second] > rw) {
deba@326: (*_node_data)[vi].heap.replace(it->second, e);
deba@326: (*_node_data)[vi].heap.decrease(e, rw);
deba@326: it->second = e;
deba@326: }
deba@326: } else {
deba@326: (*_node_data)[vi].heap.push(e, rw);
deba@326: (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e));
deba@326: }
deba@326:
deba@326: if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) {
deba@326: _blossom_set->decrease(v, (*_node_data)[vi].heap.prio());
deba@326:
deba@326: if ((*_blossom_data)[vb].status == MATCHED) {
deba@326: if (_delta2->state(vb) != _delta2->IN_HEAP) {
deba@326: _delta2->push(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset) {
deba@326: _delta2->decrease(vb, _blossom_set->classPrio(vb) -
deba@326: (*_blossom_data)[vb].offset);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326: (*_blossom_data)[blossom].offset = 0;
deba@326: }
deba@326:
deba@326: void alternatePath(int even, int tree) {
deba@326: int odd;
deba@326:
deba@326: evenToMatched(even, tree);
deba@326: (*_blossom_data)[even].status = MATCHED;
deba@326:
deba@326: while ((*_blossom_data)[even].pred != INVALID) {
deba@326: odd = _blossom_set->find(_graph.target((*_blossom_data)[even].pred));
deba@326: (*_blossom_data)[odd].status = MATCHED;
deba@326: oddToMatched(odd);
deba@326: (*_blossom_data)[odd].next = (*_blossom_data)[odd].pred;
deba@326:
deba@326: even = _blossom_set->find(_graph.target((*_blossom_data)[odd].pred));
deba@326: (*_blossom_data)[even].status = MATCHED;
deba@326: evenToMatched(even, tree);
deba@326: (*_blossom_data)[even].next =
deba@326: _graph.oppositeArc((*_blossom_data)[odd].pred);
deba@326: }
deba@326:
deba@326: }
deba@326:
deba@326: void destroyTree(int tree) {
deba@326: for (TreeSet::ItemIt b(*_tree_set, tree); b != INVALID; ++b) {
deba@326: if ((*_blossom_data)[b].status == EVEN) {
deba@326: (*_blossom_data)[b].status = MATCHED;
deba@326: evenToMatched(b, tree);
deba@326: } else if ((*_blossom_data)[b].status == ODD) {
deba@326: (*_blossom_data)[b].status = MATCHED;
deba@326: oddToMatched(b);
deba@326: }
deba@326: }
deba@326: _tree_set->eraseClass(tree);
deba@326: }
deba@326:
deba@327: void augmentOnEdge(const Edge& edge) {
deba@327:
deba@327: int left = _blossom_set->find(_graph.u(edge));
deba@327: int right = _blossom_set->find(_graph.v(edge));
deba@326:
deba@326: int left_tree = _tree_set->find(left);
deba@326: alternatePath(left, left_tree);
deba@326: destroyTree(left_tree);
deba@326:
deba@326: int right_tree = _tree_set->find(right);
deba@326: alternatePath(right, right_tree);
deba@326: destroyTree(right_tree);
deba@326:
deba@327: (*_blossom_data)[left].next = _graph.direct(edge, true);
deba@327: (*_blossom_data)[right].next = _graph.direct(edge, false);
deba@326: }
deba@326:
deba@326: void extendOnArc(const Arc& arc) {
deba@326: int base = _blossom_set->find(_graph.target(arc));
deba@326: int tree = _tree_set->find(base);
deba@326:
deba@326: int odd = _blossom_set->find(_graph.source(arc));
deba@326: _tree_set->insert(odd, tree);
deba@326: (*_blossom_data)[odd].status = ODD;
deba@326: matchedToOdd(odd);
deba@326: (*_blossom_data)[odd].pred = arc;
deba@326:
deba@326: int even = _blossom_set->find(_graph.target((*_blossom_data)[odd].next));
deba@326: (*_blossom_data)[even].pred = (*_blossom_data)[even].next;
deba@326: _tree_set->insert(even, tree);
deba@326: (*_blossom_data)[even].status = EVEN;
deba@326: matchedToEven(even, tree);
deba@326: }
deba@326:
deba@327: void shrinkOnEdge(const Edge& edge, int tree) {
deba@326: int nca = -1;
deba@326: std::vector<int> left_path, right_path;
deba@326:
deba@326: {
deba@326: std::set<int> left_set, right_set;
deba@326: int left = _blossom_set->find(_graph.u(edge));
deba@326: left_path.push_back(left);
deba@326: left_set.insert(left);
deba@326:
deba@326: int right = _blossom_set->find(_graph.v(edge));
deba@326: right_path.push_back(right);
deba@326: right_set.insert(right);
deba@326:
deba@326: while (true) {
deba@326:
deba@326: if ((*_blossom_data)[left].pred == INVALID) break;
deba@326:
deba@326: left =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[left].pred));
deba@326: left_path.push_back(left);
deba@326: left =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[left].pred));
deba@326: left_path.push_back(left);
deba@326:
deba@326: left_set.insert(left);
deba@326:
deba@326: if (right_set.find(left) != right_set.end()) {
deba@326: nca = left;
deba@326: break;
deba@326: }
deba@326:
deba@326: if ((*_blossom_data)[right].pred == INVALID) break;
deba@326:
deba@326: right =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[right].pred));
deba@326: right_path.push_back(right);
deba@326: right =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[right].pred));
deba@326: right_path.push_back(right);
deba@326:
deba@326: right_set.insert(right);
deba@326:
deba@326: if (left_set.find(right) != left_set.end()) {
deba@326: nca = right;
deba@326: break;
deba@326: }
deba@326:
deba@326: }
deba@326:
deba@326: if (nca == -1) {
deba@326: if ((*_blossom_data)[left].pred == INVALID) {
deba@326: nca = right;
deba@326: while (left_set.find(nca) == left_set.end()) {
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: right_path.push_back(nca);
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: right_path.push_back(nca);
deba@326: }
deba@326: } else {
deba@326: nca = left;
deba@326: while (right_set.find(nca) == right_set.end()) {
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: left_path.push_back(nca);
deba@326: nca =
deba@326: _blossom_set->find(_graph.target((*_blossom_data)[nca].pred));
deba@326: left_path.push_back(nca);
deba@326: }
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: std::vector<int> subblossoms;
deba@326: Arc prev;
deba@326:
deba@326: prev = _graph.direct(edge, true);
deba@326: for (int i = 0; left_path[i] != nca; i += 2) {
deba@326: subblossoms.push_back(left_path[i]);
deba@326: (*_blossom_data)[left_path[i]].next = prev;
deba@326: _tree_set->erase(left_path[i]);
deba@326:
deba@326: subblossoms.push_back(left_path[i + 1]);
deba@326: (*_blossom_data)[left_path[i + 1]].status = EVEN;
deba@326: oddToEven(left_path[i + 1], tree);
deba@326: _tree_set->erase(left_path[i + 1]);
deba@326: prev = _graph.oppositeArc((*_blossom_data)[left_path[i + 1]].pred);
deba@326: }
deba@326:
deba@326: int k = 0;
deba@326: while (right_path[k] != nca) ++k;
deba@326:
deba@326: subblossoms.push_back(nca);
deba@326: (*_blossom_data)[nca].next = prev;
deba@326:
deba@326: for (int i = k - 2; i >= 0; i -= 2) {
deba@326: subblossoms.push_back(right_path[i + 1]);
deba@326: (*_blossom_data)[right_path[i + 1]].status = EVEN;
deba@326: oddToEven(right_path[i + 1], tree);
deba@326: _tree_set->erase(right_path[i + 1]);
deba@326:
deba@326: (*_blossom_data)[right_path[i + 1]].next =
deba@326: (*_blossom_data)[right_path[i + 1]].pred;
deba@326:
deba@326: subblossoms.push_back(right_path[i]);
deba@326: _tree_set->erase(right_path[i]);
deba@326: }
deba@326:
deba@326: int surface =
deba@326: _blossom_set->join(subblossoms.begin(), subblossoms.end());
deba@326:
deba@326: for (int i = 0; i < int(subblossoms.size()); ++i) {
deba@326: if (!_blossom_set->trivial(subblossoms[i])) {
deba@326: (*_blossom_data)[subblossoms[i]].pot += 2 * _delta_sum;
deba@326: }
deba@326: (*_blossom_data)[subblossoms[i]].status = MATCHED;
deba@326: }
deba@326:
deba@326: (*_blossom_data)[surface].pot = -2 * _delta_sum;
deba@326: (*_blossom_data)[surface].offset = 0;
deba@326: (*_blossom_data)[surface].status = EVEN;
deba@326: (*_blossom_data)[surface].pred = (*_blossom_data)[nca].pred;
deba@326: (*_blossom_data)[surface].next = (*_blossom_data)[nca].pred;
deba@326:
deba@326: _tree_set->insert(surface, tree);
deba@326: _tree_set->erase(nca);
deba@326: }
deba@326:
deba@326: void splitBlossom(int blossom) {
deba@326: Arc next = (*_blossom_data)[blossom].next;
deba@326: Arc pred = (*_blossom_data)[blossom].pred;
deba@326:
deba@326: int tree = _tree_set->find(blossom);
deba@326:
deba@326: (*_blossom_data)[blossom].status = MATCHED;
deba@326: oddToMatched(blossom);
deba@326: if (_delta2->state(blossom) == _delta2->IN_HEAP) {
deba@326: _delta2->erase(blossom);
deba@326: }
deba@326:
deba@326: std::vector<int> subblossoms;
deba@326: _blossom_set->split(blossom, std::back_inserter(subblossoms));
deba@326:
deba@326: Value offset = (*_blossom_data)[blossom].offset;
deba@326: int b = _blossom_set->find(_graph.source(pred));
deba@326: int d = _blossom_set->find(_graph.source(next));
deba@326:
deba@326: int ib = -1, id = -1;
deba@326: for (int i = 0; i < int(subblossoms.size()); ++i) {
deba@326: if (subblossoms[i] == b) ib = i;
deba@326: if (subblossoms[i] == d) id = i;
deba@326:
deba@326: (*_blossom_data)[subblossoms[i]].offset = offset;
deba@326: if (!_blossom_set->trivial(subblossoms[i])) {
deba@326: (*_blossom_data)[subblossoms[i]].pot -= 2 * offset;
deba@326: }
deba@326: if (_blossom_set->classPrio(subblossoms[i]) !=
deba@326: std::numeric_limits<Value>::max()) {
deba@326: _delta2->push(subblossoms[i],
deba@326: _blossom_set->classPrio(subblossoms[i]) -
deba@326: (*_blossom_data)[subblossoms[i]].offset);
deba@326: }
deba@326: }
deba@326:
deba@326: if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) {
deba@326: for (int i = (id + 1) % subblossoms.size();
deba@326: i != ib; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: (*_blossom_data)[sb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326: }
deba@326:
deba@326: for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: int ub = subblossoms[(i + 2) % subblossoms.size()];
deba@326:
deba@326: (*_blossom_data)[sb].status = ODD;
deba@326: matchedToOdd(sb);
deba@326: _tree_set->insert(sb, tree);
deba@326: (*_blossom_data)[sb].pred = pred;
deba@326: (*_blossom_data)[sb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326:
deba@326: pred = (*_blossom_data)[ub].next;
deba@326:
deba@326: (*_blossom_data)[tb].status = EVEN;
deba@326: matchedToEven(tb, tree);
deba@326: _tree_set->insert(tb, tree);
deba@326: (*_blossom_data)[tb].pred = (*_blossom_data)[tb].next;
deba@326: }
deba@326:
deba@326: (*_blossom_data)[subblossoms[id]].status = ODD;
deba@326: matchedToOdd(subblossoms[id]);
deba@326: _tree_set->insert(subblossoms[id], tree);
deba@326: (*_blossom_data)[subblossoms[id]].next = next;
deba@326: (*_blossom_data)[subblossoms[id]].pred = pred;
deba@326:
deba@326: } else {
deba@326:
deba@326: for (int i = (ib + 1) % subblossoms.size();
deba@326: i != id; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: (*_blossom_data)[sb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326: }
deba@326:
deba@326: for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) {
deba@326: int sb = subblossoms[i];
deba@326: int tb = subblossoms[(i + 1) % subblossoms.size()];
deba@326: int ub = subblossoms[(i + 2) % subblossoms.size()];
deba@326:
deba@326: (*_blossom_data)[sb].status = ODD;
deba@326: matchedToOdd(sb);
deba@326: _tree_set->insert(sb, tree);
deba@326: (*_blossom_data)[sb].next = next;
deba@326: (*_blossom_data)[sb].pred =
deba@326: _graph.oppositeArc((*_blossom_data)[tb].next);
deba@326:
deba@326: (*_blossom_data)[tb].status = EVEN;
deba@326: matchedToEven(tb, tree);
deba@326: _tree_set->insert(tb, tree);
deba@326: (*_blossom_data)[tb].pred =
deba@326: (*_blossom_data)[tb].next =
deba@326: _graph.oppositeArc((*_blossom_data)[ub].next);
deba@326: next = (*_blossom_data)[ub].next;
deba@326: }
deba@326:
deba@326: (*_blossom_data)[subblossoms[ib]].status = ODD;
deba@326: matchedToOdd(subblossoms[ib]);
deba@326: _tree_set->insert(subblossoms[ib], tree);
deba@326: (*_blossom_data)[subblossoms[ib]].next = next;
deba@326: (*_blossom_data)[subblossoms[ib]].pred = pred;
deba@326: }
deba@326: _tree_set->erase(blossom);
deba@326: }
deba@326:
deba@326: void extractBlossom(int blossom, const Node& base, const Arc& matching) {
deba@326: if (_blossom_set->trivial(blossom)) {
deba@326: int bi = (*_node_index)[base];
deba@326: Value pot = (*_node_data)[bi].pot;
deba@326:
deba@326: _matching->set(base, matching);
deba@326: _blossom_node_list.push_back(base);
deba@326: _node_potential->set(base, pot);
deba@326: } else {
deba@326:
deba@326: Value pot = (*_blossom_data)[blossom].pot;
deba@326: int bn = _blossom_node_list.size();
deba@326:
deba@326: std::vector<int> subblossoms;
deba@326: _blossom_set->split(blossom, std::back_inserter(subblossoms));
deba@326: int b = _blossom_set->find(base);
deba@326: int ib = -1;
deba@326: for (int i = 0; i < int(subblossoms.size()); ++i) {
deba@326: if (subblossoms[i] == b) { ib = i; break; }
deba@326: }
deba@326:
deba@326: for (int i = 1; i < int(subblossoms.size()); i += 2) {
deba@326: int sb = subblossoms[(ib + i) % subblossoms.size()];
deba@326: int tb = subblossoms[(ib + i + 1) % subblossoms.size()];
deba@326:
deba@326: Arc m = (*_blossom_data)[tb].next;
deba@326: extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m));
deba@326: extractBlossom(tb, _graph.source(m), m);
deba@326: }
deba@326: extractBlossom(subblossoms[ib], base, matching);
deba@326:
deba@326: int en = _blossom_node_list.size();
deba@326:
deba@326: _blossom_potential.push_back(BlossomVariable(bn, en, pot));
deba@326: }
deba@326: }
deba@326:
deba@326: void extractMatching() {
deba@326: std::vector<int> blossoms;
deba@326: for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) {
deba@326: blossoms.push_back(c);
deba@326: }
deba@326:
deba@326: for (int i = 0; i < int(blossoms.size()); ++i) {
deba@326:
deba@326: Value offset = (*_blossom_data)[blossoms[i]].offset;
deba@326: (*_blossom_data)[blossoms[i]].pot += 2 * offset;
deba@326: for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]);
deba@326: n != INVALID; ++n) {
deba@326: (*_node_data)[(*_node_index)[n]].pot -= offset;
deba@326: }
deba@326:
deba@326: Arc matching = (*_blossom_data)[blossoms[i]].next;
deba@326: Node base = _graph.source(matching);
deba@326: extractBlossom(blossoms[i], base, matching);
deba@326: }
deba@326: }
deba@326:
deba@326: public:
deba@326:
deba@326: /// \brief Constructor
deba@326: ///
deba@326: /// Constructor.
deba@326: MaxWeightedPerfectMatching(const Graph& graph, const WeightMap& weight)
deba@326: : _graph(graph), _weight(weight), _matching(0),
deba@326: _node_potential(0), _blossom_potential(), _blossom_node_list(),
deba@326: _node_num(0), _blossom_num(0),
deba@326:
deba@326: _blossom_index(0), _blossom_set(0), _blossom_data(0),
deba@326: _node_index(0), _node_heap_index(0), _node_data(0),
deba@326: _tree_set_index(0), _tree_set(0),
deba@326:
deba@326: _delta2_index(0), _delta2(0),
deba@326: _delta3_index(0), _delta3(0),
deba@326: _delta4_index(0), _delta4(0),
deba@326:
deba@326: _delta_sum() {}
deba@326:
deba@326: ~MaxWeightedPerfectMatching() {
deba@326: destroyStructures();
deba@326: }
deba@326:
deba@326: /// \name Execution control
alpar@330: /// The simplest way to execute the algorithm is to use the
deba@326: /// \c run() member function.
deba@326:
deba@326: ///@{
deba@326:
deba@326: /// \brief Initialize the algorithm
deba@326: ///
deba@326: /// Initialize the algorithm
deba@326: void init() {
deba@326: createStructures();
deba@326:
deba@326: for (ArcIt e(_graph); e != INVALID; ++e) {
deba@327: _node_heap_index->set(e, BinHeap<Value, IntArcMap>::PRE_HEAP);
deba@326: }
deba@326: for (EdgeIt e(_graph); e != INVALID; ++e) {
deba@326: _delta3_index->set(e, _delta3->PRE_HEAP);
deba@326: }
deba@326: for (int i = 0; i < _blossom_num; ++i) {
deba@326: _delta2_index->set(i, _delta2->PRE_HEAP);
deba@326: _delta4_index->set(i, _delta4->PRE_HEAP);
deba@326: }
deba@326:
deba@326: int index = 0;
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: Value max = - std::numeric_limits<Value>::max();
deba@326: for (OutArcIt e(_graph, n); e != INVALID; ++e) {
deba@326: if (_graph.target(e) == n) continue;
deba@326: if ((dualScale * _weight[e]) / 2 > max) {
deba@326: max = (dualScale * _weight[e]) / 2;
deba@326: }
deba@326: }
deba@326: _node_index->set(n, index);
deba@326: (*_node_data)[index].pot = max;
deba@326: int blossom =
deba@326: _blossom_set->insert(n, std::numeric_limits<Value>::max());
deba@326:
deba@326: _tree_set->insert(blossom);
deba@326:
deba@326: (*_blossom_data)[blossom].status = EVEN;
deba@326: (*_blossom_data)[blossom].pred = INVALID;
deba@326: (*_blossom_data)[blossom].next = INVALID;
deba@326: (*_blossom_data)[blossom].pot = 0;
deba@326: (*_blossom_data)[blossom].offset = 0;
deba@326: ++index;
deba@326: }
deba@326: for (EdgeIt e(_graph); e != INVALID; ++e) {
deba@326: int si = (*_node_index)[_graph.u(e)];
deba@326: int ti = (*_node_index)[_graph.v(e)];
deba@326: if (_graph.u(e) != _graph.v(e)) {
deba@326: _delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot -
deba@326: dualScale * _weight[e]) / 2);
deba@326: }
deba@326: }
deba@326: }
deba@326:
deba@326: /// \brief Starts the algorithm
deba@326: ///
deba@326: /// Starts the algorithm
deba@326: bool start() {
deba@326: enum OpType {
deba@326: D2, D3, D4
deba@326: };
deba@326:
deba@326: int unmatched = _node_num;
deba@326: while (unmatched > 0) {
deba@326: Value d2 = !_delta2->empty() ?
deba@326: _delta2->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: Value d3 = !_delta3->empty() ?
deba@326: _delta3->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: Value d4 = !_delta4->empty() ?
deba@326: _delta4->prio() : std::numeric_limits<Value>::max();
deba@326:
deba@326: _delta_sum = d2; OpType ot = D2;
deba@326: if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; }
deba@326: if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; }
deba@326:
deba@326: if (_delta_sum == std::numeric_limits<Value>::max()) {
deba@326: return false;
deba@326: }
deba@326:
deba@326: switch (ot) {
deba@326: case D2:
deba@326: {
deba@326: int blossom = _delta2->top();
deba@326: Node n = _blossom_set->classTop(blossom);
deba@326: Arc e = (*_node_data)[(*_node_index)[n]].heap.top();
deba@326: extendOnArc(e);
deba@326: }
deba@326: break;
deba@326: case D3:
deba@326: {
deba@326: Edge e = _delta3->top();
deba@326:
deba@326: int left_blossom = _blossom_set->find(_graph.u(e));
deba@326: int right_blossom = _blossom_set->find(_graph.v(e));
deba@326:
deba@326: if (left_blossom == right_blossom) {
deba@326: _delta3->pop();
deba@326: } else {
deba@326: int left_tree = _tree_set->find(left_blossom);
deba@326: int right_tree = _tree_set->find(right_blossom);
deba@326:
deba@326: if (left_tree == right_tree) {
deba@327: shrinkOnEdge(e, left_tree);
deba@326: } else {
deba@327: augmentOnEdge(e);
deba@326: unmatched -= 2;
deba@326: }
deba@326: }
deba@326: } break;
deba@326: case D4:
deba@326: splitBlossom(_delta4->top());
deba@326: break;
deba@326: }
deba@326: }
deba@326: extractMatching();
deba@326: return true;
deba@326: }
deba@326:
deba@326: /// \brief Runs %MaxWeightedPerfectMatching algorithm.
deba@326: ///
deba@326: /// This method runs the %MaxWeightedPerfectMatching algorithm.
deba@326: ///
deba@326: /// \note mwm.run() is just a shortcut of the following code.
deba@326: /// \code
deba@326: /// mwm.init();
deba@326: /// mwm.start();
deba@326: /// \endcode
deba@326: bool run() {
deba@326: init();
deba@326: return start();
deba@326: }
deba@326:
deba@326: /// @}
deba@326:
deba@326: /// \name Primal solution
alpar@330: /// Functions to get the primal solution, ie. the matching.
deba@326:
deba@326: /// @{
deba@326:
deba@326: /// \brief Returns the matching value.
deba@326: ///
deba@326: /// Returns the matching value.
deba@326: Value matchingValue() const {
deba@326: Value sum = 0;
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: if ((*_matching)[n] != INVALID) {
deba@326: sum += _weight[(*_matching)[n]];
deba@326: }
deba@326: }
deba@326: return sum /= 2;
deba@326: }
deba@326:
deba@327: /// \brief Returns true when the edge is in the matching.
deba@326: ///
deba@327: /// Returns true when the edge is in the matching.
deba@327: bool matching(const Edge& edge) const {
deba@327: return static_cast<const Edge&>((*_matching)[_graph.u(edge)]) == edge;
deba@326: }
deba@326:
deba@327: /// \brief Returns the incident matching edge.
deba@326: ///
deba@327: /// Returns the incident matching arc from given edge.
deba@326: Arc matching(const Node& node) const {
deba@326: return (*_matching)[node];
deba@326: }
deba@326:
deba@326: /// \brief Returns the mate of the node.
deba@326: ///
deba@326: /// Returns the adjancent node in a mathcing arc.
deba@326: Node mate(const Node& node) const {
deba@326: return _graph.target((*_matching)[node]);
deba@326: }
deba@326:
deba@326: /// @}
deba@326:
deba@326: /// \name Dual solution
alpar@330: /// Functions to get the dual solution.
deba@326:
deba@326: /// @{
deba@326:
deba@326: /// \brief Returns the value of the dual solution.
deba@326: ///
deba@326: /// Returns the value of the dual solution. It should be equal to
deba@326: /// the primal value scaled by \ref dualScale "dual scale".
deba@326: Value dualValue() const {
deba@326: Value sum = 0;
deba@326: for (NodeIt n(_graph); n != INVALID; ++n) {
deba@326: sum += nodeValue(n);
deba@326: }
deba@326: for (int i = 0; i < blossomNum(); ++i) {
deba@326: sum += blossomValue(i) * (blossomSize(i) / 2);
deba@326: }
deba@326: return sum;
deba@326: }
deba@326:
deba@326: /// \brief Returns the value of the node.
deba@326: ///
deba@326: /// Returns the the value of the node.
deba@326: Value nodeValue(const Node& n) const {
deba@326: return (*_node_potential)[n];
deba@326: }
deba@326:
deba@326: /// \brief Returns the number of the blossoms in the basis.
deba@326: ///
deba@326: /// Returns the number of the blossoms in the basis.
deba@326: /// \see BlossomIt
deba@326: int blossomNum() const {
deba@326: return _blossom_potential.size();
deba@326: }
deba@326:
deba@326:
deba@326: /// \brief Returns the number of the nodes in the blossom.
deba@326: ///
deba@326: /// Returns the number of the nodes in the blossom.
deba@326: int blossomSize(int k) const {
deba@326: return _blossom_potential[k].end - _blossom_potential[k].begin;
deba@326: }
deba@326:
deba@326: /// \brief Returns the value of the blossom.
deba@326: ///
deba@326: /// Returns the the value of the blossom.
deba@326: /// \see BlossomIt
deba@326: Value blossomValue(int k) const {
deba@326: return _blossom_potential[k].value;
deba@326: }
deba@326:
alpar@330: /// \brief Iterator for obtaining the nodes of the blossom.
deba@326: ///
alpar@330: /// Iterator for obtaining the nodes of the blossom. This class
alpar@330: /// provides a common lemon style iterator for listing a
deba@326: /// subset of the nodes.
deba@326: class BlossomIt {
deba@326: public:
deba@326:
deba@326: /// \brief Constructor.
deba@326: ///
alpar@330: /// Constructor to get the nodes of the variable.
deba@326: BlossomIt(const MaxWeightedPerfectMatching& algorithm, int variable)
deba@326: : _algorithm(&algorithm)
deba@326: {
deba@326: _index = _algorithm->_blossom_potential[variable].begin;
deba@326: _last = _algorithm->_blossom_potential[variable].end;
deba@326: }
deba@326:
deba@326: /// \brief Conversion to node.
deba@326: ///
deba@326: /// Conversion to node.
deba@326: operator Node() const {
deba@327: return _algorithm->_blossom_node_list[_index];
deba@326: }
deba@326:
deba@326: /// \brief Increment operator.
deba@326: ///
deba@326: /// Increment operator.
deba@326: BlossomIt& operator++() {
deba@326: ++_index;
deba@326: return *this;
deba@326: }
deba@326:
deba@327: /// \brief Validity checking
deba@327: ///
deba@327: /// Checks whether the iterator is invalid.
deba@327: bool operator==(Invalid) const { return _index == _last; }
deba@327:
deba@327: /// \brief Validity checking
deba@327: ///
deba@327: /// Checks whether the iterator is valid.
deba@327: bool operator!=(Invalid) const { return _index != _last; }
deba@326:
deba@326: private:
deba@326: const MaxWeightedPerfectMatching* _algorithm;
deba@326: int _last;
deba@326: int _index;
deba@326: };
deba@326:
deba@326: /// @}
deba@326:
deba@326: };
deba@326:
deba@326:
deba@326: } //END OF NAMESPACE LEMON
deba@326:
deba@326: #endif //LEMON_MAX_MATCHING_H